WO2017155509A1

WO2017155509A1 - 6-state spin buffer and inverter

Info

Publication number: WO2017155509A1
Application number: PCT/US2016/021257
Authority: WO
Inventors: Sasikanth Manipatruni; Ian A. Young; Dmitri E. Nikonov
Original assignee: Intel Corporation
Priority date: 2016-03-07
Filing date: 2016-03-07
Publication date: 2017-09-14

Abstract

Described is an apparatus which input and output magnets, each configured to have six stable magnetic states including zero state, first state, second state, third state, fourth state, and fifth state, wherein the zero state is to point in a x-direction, wherein the first state is to point in a y-direction, wherein the second state is to point in a y-direction, wherein the third state is to point in a x-direction, wherein the fourth state is to point in a z-direction, and wherein the fifth state is to point in a z-direction. Described is an apparatus which comprises: a tri-axial anisotropy input magnet; a first spin channel region adjacent to the tri-axial anisotropy input magnet; a tri-axial anisotropy output magnet; a second spin channel region adjacent to the tri-axial anisotropy input and output magnets; and a third spin channel region adjacent to the tri-axial anisotropy output magnet.

Description

6-STATE SPIN BUFFER AND INVERTER

BACKGROUND

[0001] Majority of the electronic computation today is carried out in Boolean logic in digital computers and electronics. Boolean logic is a form of algebra in which all values are reduced to either TRUE (1) or FALSE (0). Boolean logic gates have scaled following the Moore's law as gate lengths have scaled (e.g., to 20 nm). Some limitations to Boolean logic are: limited density of logic gates limited by algebraic constrains in two level logic (Galois field-2 algebra); limited density of interconnect bandwidth limited by the number representation in base 2 number system; and limited density of memory states limited by the information content per bit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] The embodiments of the disclosure will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the disclosure, which, however, should not be taken to limit the disclosure to the specific embodiments, but are for explanation and understanding only.

[0003] Fig. 1 illustrates plots showing magnetic crystalline energy of a six state (6-

State) magnet used for forming a 6-State spin logic device, in accordance with some embodiments of the disclosure.

[0004] Figs. 2A-B illustrate a spin logic device with stacking of a 6-State magnet above a spin channel and with matched spacer, in accordance with some embodiments of the disclosure.

[0005] Fig. 3 illustrates a spin logic device with stacking of a 6-State magnet above a spin channel, with matched spacer leaving recessed metal region, in accordance with some embodiments of the disclosure.

[0006] Fig. 4A-B illustrate a spin logic device with stacking of a 6-State magnet including a filtering layer above a spin channel and with matched spacer, in accordance with some embodiments of the disclosure.

[0007] Fig. 5 illustrates a spin logic device with stacking of a 6-State magnet including a filtering layer above a spin channel and with matched spacer, in accordance with some embodiments of the disclosure. [0008] Figs. 6A-B illustrate proposed stacks for spin logic devices showing atomic templating of Heusler alloys for generating atomistic crystalline matched layers, according to some embodiments of the disclosure.

[0009] Figs. 7A-B illustrate a 6-State non-inverting spin gate or buffer injecting spins in the +/- x direction and receiving spins in the +/- x direction, in accordance with some embodiments of the disclosure.

[0010] Figs. 8A-B illustrate a 6-State non-inverting spin gate or buffer injecting spins in the +/-y direction and receiving spins in the +/-y direction, in accordance with some embodiments of the disclosure.

[0011] Figs. 9A-B illustrate a 6-State non-inverting spin gate or buffer injecting spins in the +/-z direction and receiving spins in the +/-z direction, in accordance with some embodiments of the disclosure.

[0012] Fig. 10A illustrates a 6-State inverting spin gate injecting spins in the -x direction and receiving spins in the +x direction while the magnetizations of the first and second magnets are -x and +x magnetizations, respectively, in accordance with some embodiments of the disclosure.

[0013] Fig. 10B illustrates cross-section of a 6-State inverting spin gates injecting spins in the +x direction and receiving spins in the +x direction while the magnetizations of the first and second magnets are -x and +x magnetizations, respectively, in accordance with some embodiments of the disclosure.

[0014] Fig. 11A illustrates a 6-State inverting spin gate injecting spins in the -y direction and receiving spins in the -y direction while the magnetizations of the first and second magnets are +y and -y magnetizations, respectively, in accordance with some embodiments of the disclosure.

[0015] Fig. 11B illustrates a 6-State inverting spin gate injecting spins in the +y direction and receiving spins in the +y direction while the magnetizations of the first and second magnets are -y and +y magnetizations, respectively, in accordance with some embodiments of the disclosure.

[0016] Fig. 12A illustrates a 6-State inverting spin gate injecting spins in the +z direction and receiving spins in the +z direction while the magnetizations of the first and second magnets are -z and +z magnetizations, respectively, in accordance with some embodiments of the disclosure.

[0017] Fig. 12B illustrates a 6-State inverting spin gate injecting spins in the -z direction and receiving spins in the -z direction while the magnetizations of the first and second magnets are +z and -z magnetizations, respectively, in accordance with some embodiments of the disclosure.

[0018] Fig. 13 illustrates a flipped version of the apparatus of Fig. 2, in accordance with some embodiments of the disclosure.

[0019] Fig. 14 illustrates a flowchart of a method for fabricating a spin logic device with 6-state magnets, according to some embodiments of the disclosure.

[0020] Fig. 15 illustrates a smart device or a computer system or a SoC (System-on-

Chip) with a spin logic device with 6-State magnets, according to some embodiments of the disclosure.

DETAILED DESCRIPTION

[0021] Various embodiments describe a 6-State logic memory element which has six uniquely defined logic states. In some embodiments, the six states magnetic states are separated by high energy barrier (e.g., 40 kT or 60 kT) to provide low error rate operation. In some embodiments, the energy barrier is greater than or at least 10 kT. In some

embodiments, a metal interconnect is provided which can conduct the six uniquely defined interconnect states. In some embodiments, a 6-State logic gate is described which comprises two 6-State magnetic elements sharing a spin channel. In some embodiments, the 6-State logic gate is operable to function as a buffer or non-inverting gate that can buffer or invert, respectively, spin current in six different orientations (e.g., +/- x, +/- y, and +/- z

orientations). In some embodiments, the 6-State logic gate is operable to function as an inverter that can invert an input spin current. This input spin current can be in +/- x, +/- y, or +/-z orientations.

[0022] In some embodiments, six orientations (e.g., 'Ο', ' , '2', '3', '4', and '5') are defined for the 6-state logic memory element such that the orientations 'Ο', ' , '3', and '4' are in-plane while the orientations '4' and '5' are out-of-plane. In some embodiments, with reference to a four quadrant two dimensional (2D) vector space, magnetic orientation facing +x direction (e.g., East) is orientation 'Ο'; magnetic orientation facing +y direction (e.g., North) is orientation T, magnetic orientation facing -x direction (e.g., West) is orientation '3', and magnetic orientation facing -y direction (e.g., South) is orientation '2'. In some embodiments, with reference to an eight quadrant three dimensional (3D), magnetic orientation facing -z direction is orientation '4' and magnetic orientation facing +z direction is orientation '5'. [0023] The 6-State magnet of the various embodiments enables high density memory and high logic circuit efficiency. Interconnect for carrying the six states provide high interconnect density per pitch, in accordance with some embodiments. Other technical effects will be evident from the various embodiments and figures.

[0024] In the following description, numerous details are discussed to provide a more thorough explanation of embodiments of the present disclosure. It will be apparent, however, to one skilled in the art, that embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring embodiments of the present disclosure.

[0025] Note that in the corresponding drawings of the embodiments, signals are represented with lines. Some lines may be thicker, to indicate more constituent signal paths, and/or have arrows at one or more ends, to indicate primary information flow direction. Such indications are not intended to be limiting. Rather, the lines are used in connection with one or more exemplary embodiments to facilitate easier understanding of a circuit or a logical unit. Any represented signal, as dictated by design needs or preferences, may actually comprise one or more signals that may travel in either direction and may be implemented with any suitable type of signal scheme.

[0026] Throughout the specification, and in the claims, the term "connected" means a direct physical, electrical, or wireless connection between the things that are connected, without any intermediary devices. The term "coupled" means either a direct electrical or wireless connection between the things that are connected or an indirect electrical or wireless connection through one or more passive or active intermediary devices. The term "circuit" means one or more passive and/or active components that are arranged to cooperate with one another to provide a desired function. The term "signal" means at least one current signal, voltage signal, magnetic signal, electromagnetic signal, or data/clock signal. The meaning of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on."

[0027] The terms "substantially," "close," "approximately," "near," and "about," generally refer to being within +/- 10% of a target value (unless specifically specified).

Unless otherwise specified the use of the ordinal adjectives "first," "second," and "third," etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking or in any other manner. [0028] Unless otherwise specified the use of the ordinal adjectives "first," "second," and "third," etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking or in any other manner.

[0029] For the purposes of the present disclosure, phrases "A and/or B" and "A or B" mean (A), (B), or (A and B). For the purposes of the present disclosure, the phrase "A, B, and/or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C). The terms "left," "right," "front," "back," "top," "bottom," "over," "under," and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions.

[0030] Fig. 1 illustrates plots 101a and 101b showing magnetic crystalline energy of a six state magnet used for forming a 6-State spin logic device, in accordance with some embodiments of the disclosure. For plot 101a, the x-axis is in-plane angle in degrees, and the y-axis is Energy in kT (where 'k' is Boltzmann constant and ' is temperature). Plot 101a illustrates two waveforms— 102 and 103. Waveforms 102 and 103 illustrate the thermal energy separation or barrier between four in-plane magnetic orientations of the 6-State magnet 107, where waveform 102 has a barrier separation of 40 kT and waveform 103 has a barrier separation of 60 kT.

[0031] The other two magnetic orientations of the 6-State magnet 107 are out-of- plane as shown by plot 101b. For plot 101b, the x-axis is out-of-plane angle in degrees, and the y-axis is Energy in kT. Plot 101b illustrates three waveforms— 104, 105, and 106.

Waveforms 104, 105, and 106 illustrates the thermal energy separation or barrier between two out-of-plane magnetic orientations of the 6-state magnet 107, where waveform 104 has a barrier separation of 20 kT, waveform 105 has a barrier separation of 40 kT, and waveform 106 has a barrier separation of 60 kT. While the embodiments described here assume a barrier separation of 40 kT, materials and shape anisotropy for 6-State magnet 107 can be selected to have other barrier separations which are large enough to provide zero error rate between states. For example, the energy barrier can be greater than or at least 10 kT.

[0032] In some embodiments, the six orientations are defined for the 6-State logic memory element such that orientations '0' and T are separated by 90 degrees, orientations T and '3' are separated by 90 degrees, orientations '3' and '2' are separated by 90 degrees, orientations '0' and '3' are separated by 180 degrees, orientations T and '2' are separated by 180 degrees, orientations '0' and '4', '4' and T, '4' and '3', and '4' and '2' are separated by 90 degrees each, orientations '5' and 'Ο', '5' and '2', '5' and '3', and '5' and T, are separated by 90 degrees each, and orientations '5' and '4' are separated by 180 degrees.

[0033] In some embodiments, with reference to an eight quadrant 3D vector space, magnetic orientation facing +x direction (e.g., East) is orientation 'Ο'; magnetic orientation facing +y direction (e.g., North) is orientation T, magnetic orientation facing -x direction (e.g., West) is orientation '3', magnetic orientation facing -y direction (e.g., South) is orientation '2', magnetic orientation facing -z direction is orientation '4', and magnetic orientation facing +z direction is orientation '5. '

[0034] In some embodiments, 6-State magnet 107 is formed using cubic magnetic crystalline anisotropy magnets. In some embodiments, 6-State magnet 107 is formed using shape, crystalline and strain assisted magnetization. One such example is illustrated as a side view of top view of 6-State magnet 107. In the side view, 6-State magnet is formed by combining a magnetostrictive (MS) ferromagnet (FM) 107a with a piezo-electric (PZe) layer 108. MS FM 107a is formed of ferromagnetic materials that causes the materials to change their shape or dimensions during the process of magnetization.

[0035] PZe layer 108 causes piezo-electric effect in magnetostrictive FM 107a when a voltage is applied to PZe layer 108. The applied voltage across PZe layer 108 causes change in the magnetic field in MS FM 107a and so it stresses magnetostrictive FM 107a. The stress in turn causes magnetostrictive FM 107a to have six magnetic states. In some embodiments, magnetostrictive FM 107a is formed of any one of the materials: Terfenol-D (an alloy of the formula Tb_xDyi-_xFe2 (x ~ 0.3)), galfenol (an alloy of iron and gallium), amorphous alloy Fe8iSi3.5B13.5C2, or Ni.

[0036] In some embodiments, PZe layer 108 is formed of any one of the materials:

Barium titanate (BaTi03), Lead zirconate titanate (PZT), Potassium niobate (KNb03), Sodium tungstate (Na2W03), Ba2NaNb505, Pb2K b50i5, Zinc oxide (ZnO)-Wurtzite structure, Sodium potassium niobate ((K,Na)Nb03) (or NKN), Bismuth ferrite (BiFe03), Sodium niobate NaNb03, Bismuth titanate Βΐ4Τΐ3θΐ2, Sodium bismuth titanate Nao.5Bio.5Ti03, any bulk or nanostructured semiconductor crystal having non central symmetry, such as the Group III-V and II-VI materials, Polyvinylidene fluoride (PVDF), diphenylalanine peptide nanotubes (PNTs), etc.

[0037] In some embodiments, 6-State magnet 107 is formed using shape, exchange coupling and strain assisted magnetization. In some embodiments, 6-State magnet 107 is formed using in-plane bi-axial anisotropy and strain assisted magnetization. In some embodiments, 6-State magnet 107 is formed using tri-axial anisotropy magnet. [0038] In some embodiments, 6-State magnet 107 is formed of a material selected from a group consisting of: Fe, Ni, Co and their alloys, magnetic insulators, and Heusler alloys of the form ¾YZ. In some embodiments, the magnetic insulators are formed of a material selected from a group consisting of: magnetite Fe₃0₄ and Y3AI5O12. In some embodiments, the Heusler alloys is one of: Co₂FeSi and M Ga.

[0039] In some embodiments, 6-State magnet 107 is formed with high spin polarization materials. Heusler alloys are an example of high spin polarization materials. Heusler alloys are ferromagnetic metal alloys based on Heusler phase. Heusler phases are intermetallics with particular composition and face-centered cubic crystal structure. Heusler alloys are ferromagnetic because of double-exchange mechanism between neighboring magnetic ions. The neighboring magnetic ions are usually manganese ions, which sit at the body centers of the cubic structure and carry most of the magnetic moment of the alloy.

[0040] In some embodiments, 6-State magnet 107 is formed with a sufficiently high anisotropy (Hk) and sufficiently low magnetic saturation (M_s) to increase injection of spin currents. For example, Heusler alloys of high Hk and low M_s are used to form 6-State magnet 107.

[0041] Magnetic saturation M_s is generally the state reached when an increase in applied external magnetic field H cannot increase the magnetization of the material (i.e., total magnetic flux density B substantially levels off). Here, sufficiently low M_s refers to M_s less than 200 kA/m (kilo-Amperes per meter). Anisotropy Hk generally refers to the material property which is directionally dependent. Materials with Hk are materials with material properties that are highly directionally dependent. Here, sufficiently high Hk in context of Heusler alloys is considered to be greater than 2000 Oe (Oersted). For example, a half metal that does not have bandgap in spin up states but does have bandgap in spin down states (e.g., at the energies within the bandgap, the material has 100% spin up electrons). If the Fermi level of the material is in the bandgap, injected electrons will be close to 100% spin polarized. In this context, "spin up" generally refers to the positive direction of

magnetization, and "spin down" generally refers to the negative direction of magnetization. Variations of the magnetization direction (e.g. due to thermal fluctuations) result in mixing of spin polarizations.

[0042] In some embodiments, Heusler alloys such as Co2FeAl and Co2FeGeGa are used for forming 6-state magnet 107. Other examples of Heusler alloys include: Cu₂MnAl, Cu₂MnIn, Cu₂MnSn, Ni₂MnAl, Ni₂MnIn, Ni₂MnSn, Ni₂MnSb, Ni₂MnGa, Co₂MnAl, Co₂MnSi, Co₂MnGa, Co₂MnGe, Pd₂MnAl, Pd₂MnIn, Pd₂MnSn, Pd₂MnSb, Co₂FeSi, Fe₂Val, Mn₂VGa, Co₂FeGe, etc.

[0043] Figs. 2A-B illustrate cross-sections of spin logic devices 200 and 230, respectively, with stacking of a 6-State magnet above a spin channel and with matched spacer, in accordance with some embodiments of the disclosure. Fig. 2A also illustrates top view 220 of a cross-section XX of spin logic device 200. It is pointed out that those elements of Figs. 2A-B having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such. Here, cross-section 200 of spin logic device is also referred to as spin logic device 200 or device 200.

[0044] With reference to Fig. 2A, in some embodiments, device 200 comprises a first metal layer 201a, First 6-State Magnet 203a, Second 6-State Magnet 203b, Oxide 205a between First and Second 6-State Magnets 203a/b, Spin Channel 206 a/b/c, Oxide layer 205b over Spin Channel 206a/b/c, Via 207, and second metal layer 201b. Here, Power and Ground metal layers 201a and 201b, respectively, may be collectively referred to as metal layers 201 ; First and Second 6-State Magnets 203a and 203b, respectively, may be collectively referred to as 6-State Magnets 203; Oxide layers 205a and 205b may be collectively referred to as oxide 205; and Spin Channel 206a/b/c may be collectively referred to as Spin Channel 206.

[0045] In some embodiments, the material(s) used for forming metal layers 201, Via

207, and Spin Channel 206 is/are the same. For example, Copper (Cu) can be used for forming metal layers 201, Via 207, and Spin Channel 206. In other embodiments, material(s) used for forming metal layers 201, Via 207, and Spin Channel 206 are different. For example, metal layers 201 may be formed of Cu while Via 207 may be formed of Tungsten (W). Any suitable metal or combination of metals can be used for forming metal layers 201, Via 207, and Spin Channel 206. For example, Spin Channel 206 can be formed of Silver (Ag), Aluminum (Al), Graphene, and other 2D conducting materials. In some embodiments, the 2D conducting materials are selected from a group consisting of: graphene, M0S2, MoSe, WS, WSe, and other chalcogenide materials. In some embodiments, First and Second 6-State Magnets 203a/b are formed of the same materials as described with reference to 6-State magnet 107 and 107a.

[0046] In some embodiments, Spin Channel 206 is partitioned into segments or regions 206a, 206b, and 206c such that Oxide 205b forms a barrier between the channel segments. One purpose of the barrier is to control the transfer of spin to charge. In some embodiments, the gap between First and Second 6-State Magnets 203a/b, provided by Oxide 205b, is chosen to be sufficient to permit isolation of the two magnets 203a/b. In some embodiments, a layer of oxide 205b is deposited before the Spin Channel 206 and then a via hole is etched for Via 207. In some embodiments, Via 207 couples Channel segment 206b to Ground supply layer 201b which is formed over Oxide layer 205b.

[0047] In some embodiments, spin device 200 of Fig. 2A is inverted. For example, magnetic contacts 203 of device 200 are placed below Spin Channel 206. As such, magnetic contacts 203 are closer to the bottom than the top as opposed to placing the magnets of device closer to the top than the bottom. Top view 220 shows the top view of the cross-section XX of cross-section 200, in accordance with some embodiments. Here, the six orientations of the six states of First and Second 6-State Magnets 203a/b are shown. In some embodiments, First and Second 6-State Magnets 203a/b are cube (or square) shaped. As such, each magnetic state of First and Second 6-State Magnets 203a/b is separated by the same barrier energy (e.g., 40 kT).

[0048] In some embodiments, First 6-State Magnet 203 a dictates the flow of the spin current in channel 206b. This is realized by the asymmetry of First 6-State Magnet 203a overlap with channel 206b. Here, First 6-State Magnet 203a overlaps more with channel 206b than Second 6-State Magnet 203b. This asymmetry in the overlap sets the direction of spin through channel 206b, in accordance with some embodiments.

[0049] With reference to Fig. 2B, in some embodiments, the 6-State input and output magnets of spin device 230 are formed by a stack of magnetostrictive magnet and PZe layer as described with reference to the side view in Fig. 1. Fig. 2B also illustrates top view 240 of a cross-section XX of spin logic device 230. Here, the first input magnet is formed by a stack of First MS magnet 233a and PZe layer 234a, while the second input magnet is formed by Second MS magnet 233b and PZe layer 234b. Functionally, spin device 230 is similar to spin device 200 except for formation of the 6-State magnets.

[0050] Fig. 3 illustrates spin logic device 300 (or cross-section 300) with stacking of a 6-State magnet above or below a spin channel, with matched spacer leaving recessed metal region, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Fig. 3 having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such. So as not to obscure the embodiments, differences between spin logic devices of Fig. 3 and Fig. 2A are described.

[0051] In some embodiments, spin logic device 300 comprises first filter layer 301a and second filter layer 301b. In some embodiments, first filter layer 301a is formed between First 6-State Magnet 203a and the portions of channel regions (or segments) 206a and 206b. As such, unlike First 6-State Magnet 203a being directly coupled or adjacent to the portions of channel regions (or segments) 206a and 206b as described with reference to Fig. 2A, here First 6-State Magnet 203a is coupled or adjacent to first filter layer 301a. In some embodiments, second filter layer 301b is formed between Second 6-State Magnet 203b and the portions of channel regions (or segments) 206c and 206b. As such, unlike Second 6-State Magnet 203a being directly coupled to or adjacent to the portions of channel regions (or segments) 206a and 206b, here Second 6-State Magnet 203b is coupled to or is adjacent to second filter layer 301b.

[0052] In some embodiments, first and second filter layers 301 a/b are formed of a material selected from a group consisting of: MgO, AI2O3, BN, MgAk04, ZnAh04,

SiMg204, and SiZmC , and NiFeO. One purpose of the filter layers is to provide high tunneling magnetoresistance.

[0053] In some embodiments, First 6-State magnet 203a and the first filter layer 301a overlap the spin channel region 206b more than Second 6-state magnet 203b and second filter layer 301b overlap the second spin channel region. This asymmetry in the overlap sets the direction of spin through channel 206b, in accordance with some embodiments.

[0054] Figs. 4A-B illustrate spin logic devices 400 and 420 with stacking of a 6-State magnet, respectively, including a filtering layer above or below a spin channel and with matched spacer, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Figs. 4A-B having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[0055] Fig. 4A is similar to Fig. 2A except that Oxide barriers 205b are not complete barriers between segments of Spin Channel 206. Fig. 4B is similar to Fig. 2B except that Oxide barriers 205b are not complete barriers between segments of Spin Channel 206. As such, Spin Channel 401 has sections of metal above Oxide barriers 205b for coupling the channel segments. One reason for having recessed metal region under Oxide barriers 205b is to control the rate of exchange of spin between channel segments. In some embodiments, the height or thickness of the recessed metal region controls the rate of exchange of spin. For example, the thicker the recessed metal region (i.e., lesser the metal recession) the higher the rate of exchange of spin. The embodiments of Figs. 4A-B provide an alternative way of connecting spin devices. In some embodiments, spin logic devices 200/230/300/400/420 are integrated to form majority gate spin logic devices. [0056] Fig. 5 illustrates spin logic device 500 with stacking of a 6-State magnet including engineered interfaces coupled to the spin channel, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Fig. 5 having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[0057] In some embodiments, engineered interfaces (i.e., first and second interfaces

504a/b and 502, respectively) are formed between the magnets (i.e., First and Second 6-State Magnets 203a/b) and metal layers (e.g., Ground 201b and Spin Channel 206a). In some embodiments, the dimensions (e.g., width, length, and height/thickness) of Ground 201b is chosen to optimize (e.g., reduce) the energy-delay of spin device 200. In some embodiments, first and second interfaces 504a/b and 502, respectively, are formed of non-magnetic material(s) such that the interface layers and the magnets together have sufficiently matched atomistic crystalline layers. For example, the non-magnetic material has a crystal periodicity which is matched through rotation or by mixing of elements.

[0058] Here, sufficiently matched atomistic crystalline layers refer to matching of the lattice constant 'a' within a threshold level above which atoms exhibit dislocation which is harmful to the device (i.e., the number and character of dislocations lead to a significant (e.g., greater than 10%) probability of spin flip while an electron traverses the interface layer). For example, the threshold level is within 5% (i.e., threshold levels in the range of 0% to 5% of the relative difference of the lattice constants). As the matching improves (e.g., matching gets closer to perfect matching), spin injection efficiency from spin transfer from 6-State magnets 203 to Spin Channel 206 increases. Poor matching (e.g., matching worse than 5%) implies dislocation of atoms that is harmful for the device. In some embodiments, the nonmagnetic material is Ag with a crystal lattice constant a=4.05A which is matched to Heusler alloys CFA (i.e., Co₂FeAl) and CFGG (i.e., Co₂FeGeGa with a=5.737A) provided the direction of the crystal axes is turned by 45 degrees. Then the projection of the lattice constant is expressed as:

al 2 « 5.737_4/ 1.414 « 4.057.4

As such, the magnetic structure stack (e.g., stack of 203a and 504a) allows for interfacial matching of Heusler alloys interfaces with the spin channel. In some embodiments, the stack also allows for templating of the bottom surface of the Heusler alloy.

[0059] In some embodiments, interface layer 502 (e.g., Ag) provides electrical contact to magnets 203. As such, a template is provided with the right crystal orientation to seed the formation of the Heusler alloy (which forms 6-State magnets 203). In some embodiments, the directionality of spin logic may be set by the geometric asymmetry in spin device 200. In some embodiments, the area of overlap of First 6-State magnet 203a (e.g., the input magnet) with Spin Channel 206b is larger than the area of overlap of Second 6-State magnet 203b (e.g., the output magnet) causing asymmetric spin in channel 206b.

[0060] One technical effect of the engineered interface layers 504a/b (e.g., Ag) between Heusler alloy based magnets 203a/b and Spin Channel 206 is that it provides for higher mechanical barrier to stop or inhibit the inter-diffusion of magnetic species with Spin Channel 206. In some embodiments, the engineered interface layers 504a/b maintain high spin injection at the interface between Spin Channel 206 and magnets 203. As such, engineered interface layers 504a/b improve the performance of spin device 200.

[0061] In some embodiments, the fabrication of Heusler alloy and the matching layer is via the use of an in situ processing flow. Here, in situ processing flow refers to a fabricating processing flow that does not break vacuum. As such, oxidation on interface 504 are avoided resulting in smooth surfaces at interface 504.

[0062] In some embodiments, First 6-State magnet 203a and the first interface layer

504a overlap the spin channel region 206b more than Second 6-State magnet 203b and second interface layer 504b overlap the second spin channel region. This asymmetry in the overlap sets the direction of spin through channel 206b, in accordance with some

embodiments.

[0063] Figs. 6A-B illustrate proposed stacks 600 and 620, respectively, for spin logic devices showing atomic templating of Heusler alloys for generating atomistic crystalline matched layers, according to some embodiments of the disclosure. It is pointed out that those elements of Figs. 6A-B having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[0064] Stacks 600 and 620 illustrate a naturally templated magnet using the magnetic structure of some embodiments. A characteristic of templated stacks is that the crystalline growth of a layer is not adversely affected by the crystal symmetry of the underlying layer. Stacks 600 and 620 are a stack of interface layer 502 (e.g., Ag), magnet layer 203a/b, and interface layer 504a/b (e.g., Ag). Stack 600 shows matching of Ag with Co2FeAl while stack 620 shows matching of Ag with Co2FeGeGa. Here, there is a 2% difference in crystal periodicity which makes the interface between Ag with Co2FeAl, and Ag with Co2FeGeGa, well matched (e.g., Ag has a crystal periodicity which is matched well with the magnet through in-plane rotation).

[0065] In some embodiments, the direction of the injected spins is reverse of the magnet polarity for inverter. The direction of spins in the channel below the two magnets can be the same. For inverter, the spins under the injection magnet is opposite of the injector while for a buffer, the direction is identical, in accordance with some embodiments.

[0066] Figs. 7A-B illustrate cross-sections 700 and 720 of a 6-State non-inverting spin gate or buffer, respectively, injecting spins in the +/- x direction and receiving spins in the +/- x direction, respectively, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Figs. 7A-B having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[0067] In some embodiments, the spin injection from the 6-State magnets is setup to produce a spin population in the spin interconnect such that a spin current is generated that flows along the channel. Here, spin current in the +x direction is in channel region 206a under the First 6-State Magnet 203a. This spin current is also referred to as the injected spin current (e.g., injected in channel region 206a). The dominant spin current is shown by spin direction 701 in the +x direction while some minority spin 702 in channel 206a points in the -x direction.

[0068] With reference to Fig. 7A, in some embodiments, when a negative voltage

(e.g., -Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 200 behaves as a buffer. In this case, if the magnetic orientation of First 6-State Magnet 203a (i.e., the input magnet) is in +x direction (i.e., M=+x), it causes the majority of spins to traverse through channel 206b towards Second 6-State Magnet 203b (i.e., the output magnet). The spins (e.g., majority and minority spins) in channel region 206b are shown by the arrows channel 206b. The magnetic orientation of Second 6-State Magnet 203b is switched to the +x direction (i.e., M=+x) due to spin torque from the received spin current 703 in the +x direction. Spin current 703 is the spin current in channel region 206c under Second 6-State Magnet 206b. As such, the 6-State magnets allow the injected +x direction spin current 701 to be received as spin current 703 in the same direction (i.e., +x direction) at the receiving channel 206c.

[0069] With reference to Fig. 7B, in some embodiments, when a negative voltage

(e.g., -Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 200 behaves as a buffer. In this case, if the magnetic orientation of First 6-State Magnet 203a (i.e., the input magnet) is in -x direction (i.e., M=-x), it causes the majority of spins to traverse through channel 206b towards Second 6-State Magnet 203b (i.e., the output magnet). The spins (e.g., majority and minority spins) in channel region 206b are shown by the arrows channel 206b. The magnetic orientation of Second 6-State Magnet 203b is switched to the -x direction (i.e., M=-x) due to spin torque from the received spin current 703 in the +x direction. Spin current 703 is the spin current in channel region 206c under Second 6-State Magnet 206b. As such, the 6-State magnets allow the injected -x direction spin current 721 to be received as spin current 723 in the same direction (i.e., -x direction) at the receiving channel 206c.

[0070] In some embodiments, the input magnet 203a dictates the flow of the spin current in channel 206b. This is realized by the asymmetry of First 6-State Magnet 203a overlapping with channel 206c. Here, First 6-State Magnet 203a overlaps more with channel 206b than Second 6-State Magnet 203b. In some embodiments, when -Vdd voltage is applied to metal layer 201a, the direction of the spin current in channel 206b is the same as the direction of the spins of First 6-State Magnet 203a. As such, a flow of spin current from First 6-State Magnet 203a to Second 6-State Magnet 203b occurs comprising of spins with the polarity of First 6-State Magnet 203a. For the buffer (or non-inverting gates of Figs. 7A- B), the spins under the input magnet 203a are identical to the spins under the output magnet 203b, in accordance with some embodiments.

[0071] Figs. 8A-B illustrate cross-sections 800 and 820 of a 6-state non-inverting spin gate or buffer, respectively, in which spins in +/- y direction are injected and spins in +/- y direction are received, respectively, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Figs. 8A-B having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[0072] With reference to Fig. 8A, spin current in the +y direction is in channel region

206a under the First 6-State Magnet 203a. This spin current is also referred to as the injected spin current (e.g., injected in channel region 206a). The dominant spin current is shown by spin direction 801 in the +y direction while minority spin 802 in channel 206a points in the - y direction.

[0073] In some embodiments, when a negative voltage (e.g., -Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 200 behaves as a buffer. In this case, the magnetic orientation of First 6-State Magnet 203a (i.e., input magnet) in +y direction (i.e., M=+y pointing out of the figure) influences the majority of spins in +y direction to traverse through channel 206b towards Second 6-State Magnet 203a (i.e., the output magnet). The magnetic orientation of Second 6-State Magnet 203b is switched to the +y direction (i.e., M=+y pointing out of the figure) due to spin torque produced by the received spin current 803 in the +y direction. As such, the 6-state magnets allow the injected +y direction spin current 801 to be received in the same direction (i.e., +y direction) at the receiving channel 206c.

[0074] With reference to Fig. 8B, spin current in the -y direction is in channel region

206a under the First 6-State Magnet 203a. This spin current is also referred to as the injected spin current (e.g., injected in channel region 206a). The dominant spin current is shown by spin direction 821 in the -y direction while minority spin 822 in channel 206a points in the +y direction.

[0075] In some embodiments, when a negative voltage (e.g., -Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 200 behaves as a buffer. In this case, the magnetic orientation of First 6-State Magnet 203a (i.e., input magnet) in -y direction (i.e., M=-y pointing into the figure) influences the majority of spins in -y direction to traverse through channel 206b towards Second 6-State Magnet 203a (i.e., the output magnet). The magnetic orientation of Second 6-State Magnet 203b is switched to the -y direction (i.e., M=-y pointing into the figure) due to spin torque produced by the received spin current 823 in the -y direction. As such, the 6-State magnets allow the injected -y direction spin current 821 to be received in the same direction (i.e., -y direction) at the receiving channel 206c.

[0076] In some embodiments, the input magnet 203a dictates the flow of the spin current in channel 206b. This is realized by the asymmetry of First 6-State Magnet 203a overlap with channel 206c. Here, First 6-State Magnet 203a overlaps more with channel 206b than Second 6-State Magnet 203b. In some embodiments, when -Vdd voltage is applied to metal layer 201a, the direction of the spin current in channel 206b is the same as the direction of the spins of First 6-State Magnet 203a. As such, a flow of spin current from First 6-State Magnet 203a to Second 6-State Magnet 203b occurs comprising of spins with polarity of First 6-State Magnet 203a. In this example, the prevalence of majority spin current relative to minority spin current decreases along the channel (i.e., decreases from channel region 206a to channel region 206c). For the buffer (or non-inverting gates of Figs. 8A-B), the spins under the input magnet 203 a is identical to the spins under the output magnet 203b, in accordance with some embodiments. [0077] Figs. 9A-B illustrate cross-sections 900 and 920 of 6-State non-inverting spin gate or buffers, respectively, injecting spins in the +/-z direction and receiving spins in the +/- z direction, respectively, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Figs. 9A-B having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[0078] With reference to Fig. 9A, spin current in the -z direction is in channel region

206a under the First 6-State Magnet 203a. This spin current is also referred to as the injected spin current (e.g., injected in channel region 206a). The dominant spin current is shown by spin direction 901 in the -z direction while minority spin 902 in channel 206a points in the +z direction.

[0079] In some embodiments, when a negative voltage (e.g., -Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 200 behaves as a buffer. In this case, the magnetic orientation of First 6-State Magnet 203a (i.e., input magnet) in -z direction (i.e., M=-z pointing up or North in the figure) influences the majority of spins in the -z direction to traverse through channel 206b towards Second 6-State Magnet 203a (i.e., the output magnet). The magnetic orientation of Second 6-State Magnet 203b is switched to the - z direction (i.e., M=-z pointing up or North in the figure) due to spin torque produced by the received spin current 903 in the -z direction. As such, the 6-State magnets allow the injected -z direction spin current 901 to be received in the same direction (i.e., -z direction) at the receiving channel 206c.

[0080] With reference to Fig. 9B, spin current in the +z direction is in channel region

206a under the First 6-State Magnet 203a. This spin current is also referred to as the injected spin current (e.g., injected in channel region 206a). The dominant spin current is shown by spin direction 921 in the +z direction while minority spin 922 in channel 206a points in the -z direction.

[0081] In some embodiments, when a negative voltage (e.g., -Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 200 behaves as a buffer. In this case, the magnetic orientation of First 6-State Magnet 203a (i.e., input magnet) in the +z direction (i.e., M=+z pointing into the figure) influences the majority of spins in +z direction to traverse through channel 206b towards Second 6-State Magnet 203a (i.e., the output magnet). The magnetic orientation of Second 6-State Magnet 203b is switched to the +z direction (i.e., M=+z pointing down or South in the figure) due to spin torque produced by the received spin current 923 in the +z direction. As such, the 6-state magnets allow the injected +z direction spin current 921 to be received in the same direction (i.e., +z direction) at the receiving channel 206c.

[0082] In some embodiments, the input magnet 203a dictates the flow of the spin current in channel 206b. This is realized by the asymmetry of First 6-State Magnet 203a overlap with channel 206c. Here, First 6-State Magnet 203a overlaps more with channel 206b than Second 6-State Magnet 203b. In some embodiments, when -Vdd voltage is applied to metal layer 201a, the direction of the spin current in channel 206b is the same as the direction of the spins of First 6-State Magnet 203a. As such, a flow of spin current from First 6-State Magnet 203a to Second 6-State Magnet 203b occurs comprising of spins with polarity of First 6-State Magnet 203a. In this example, the prevalence of majority spin current relative to minority spin current decreases along the channel (i.e., decreases from channel region 206a to channel region 206c). For the buffer (or non-inverting gates of Figs. 9A-B), the spins under input magnet 203 a are identical to the spins under output magnet 203b, in accordance with some embodiments. Here, the majority spins in channel 206c under Second Magnet 203b are spins 923.

[0083] Fig. 10A illustrates cross-section 1000 of a 6-State inverting spin gate injecting spins in the -x direction and receiving spins in the -x direction while the

magnetizations of the first and second magnets are -x and +x magnetizations, respectively, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Fig. 10A having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[0084] Here, spin current in the -x direction is injected in channel region 206a. Note, here input magnet 203a is magnetized +x (i.e., M=+x), the spin under input magnet 203a is in the -x direction, and the spin under channel region 206b is in the -x direction. The dominant spin current is shown by spin direction 1001 in the -x direction while some minority spin 1002 in channel 206a points in the +x direction. The propagation of the spin current through device 1000 depends on the magnetization of First and Second 6-State Magnets 203a/b. The spin current received in channel region 206c is in the -x direction. The prevalence of majority spin current relative to minority spin current decreases along the channel (i.e., decreases from channel region 206a to channel region 206c).

[0085] In some embodiments, when a positive voltage (e.g., +Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 1000 behaves as an inverter. In this case, the magnetic orientation of First 6-State Magnet 203a (i.e., the input magnet) is in +x direction causing the majority of spins to traverse through channel 206b towards Second 6-State Magnet 203a (i.e., the output magnet). In some embodiments, the input magnet (203 a) dictates the flow of the spin current in channel 206b. This is realized by the asymmetry of the magnet overlap with the channel. For example, First 6-State Magnet 203a overlaps more with channel 206b than Second 6-State Magnet 203a.

[0086] In some embodiments, a flow of spin current from First 6-State Magnet 203a to Second 6-State Magnet 203b occurs comprising of spins with opposite polarity of First 6- State Magnet 203a (e.g., the ratio of majority spin current relative to minority spin current decreases along the channel from channel region 206a to channel region 206c). In some embodiments, for an inverter, the direction of the injected spins is reverse of the magnet polarity. For example, the direction of majority spins 1001 is in the -x direction while the direction of magnetization of Second Magnet 203b is in the +x direction. In some embodiments, the direction of spins in channel region 206b below the two magnets can be the same for an inverter. Here, the majority spins in channel 206c under Second Magnet 203b are spins 1003.

[0087] Fig. 10B illustrates cross-section 1020 of a 6-State inverting spin gate, respectively, injecting spins in the +x direction and receiving spins in the +x direction while the magnetizations of the first and second magnets are -x and +x, respectively, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Fig. 10B having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[0088] Here, spin current in the -x direction is injected in channel region 206a. Note, here input magnet 203a is magnetized -x (i.e., M=-x), the spin under input magnet 203a is in the +x direction, and the spin under channel region 206b is in the +x direction. The dominant spin current is shown by spin direction 1021 in the +x direction while some minority spin 1002 in channel 206a points in the -x direction. The propagation of the spin current through device 1020 depends on the magnetization of First and Second 6-State Magnets 203a/b. The spin current received in channel region 206c is in the +x direction. The prevalence of majority spin current relative to minority spin current decreases along the channel (i.e., decreases from channel region 206a to channel region 206c).

[0089] In some embodiments, when a positive voltage (e.g., +Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 1020 behaves as an inverter. In this case, the magnetic orientation of First 6-State Magnet 203a (i.e., the input magnet) is in -x direction causing the majority of spins to traverse through channel 206b towards Second 6-State Magnet 203a (i.e., the output magnet). In some embodiments, the input magnet (203 a) dictates the flow of the spin current in channel 206b. This is realized by the asymmetry of the magnet overlap with the channel. For example, First 6-State Magnet 203a overlaps more with channel 206b than Second 6-State Magnet 203a.

[0090] In some embodiments, a flow of spin current from First 6-State Magnet 203a to Second 6-State Magnet 203b occurs comprising of spins with opposite polarity of First 6- State Magnet 203a (e.g., the ratio of majority spin current relative to minority spin current decreases along the channel from channel region 206a to channel region 206c). In some embodiments, for an inverter, the direction of the injected spins is reverse of the magnet polarity. For example, the direction of majority spins 1021 is in the +x direction while the direction of magnetization of Second Magnet 203b is in the -x direction. In some embodiments, the direction of spins in channel region 206b below the two magnets can be the same for an inverter. Here, the majority spins in channel 206c under Second Magnet 203b are spins 1023.

[0091] Fig. 11A illustrates a cross-section 1100 of a 6-State inverting spin gate injecting spins in the -y direction and receiving spins in the -y direction while the

magnetizations of the first and second magnets are +y and -y, respectively, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Fig. 11A having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[0092] Here, spin current in the -y direction is injected in channel region 206a. The dominant spin current is shown by spin direction 1101 in the -y direction while some minority spin 1102 in channel 206a points in the +y direction. The propagation of the spin current through device 1100 depends on the magnetization of First and Second 6-State Magnets 203a/b.

[0093] In some embodiments, when a positive voltage (e.g., +Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 1100 behaves as an inverter. In this case, the magnetic orientation of First 6-State Magnet 203a (i.e., input magnet) is in +y direction (i.e., M=+y) causing the majority of spins to traverse through channel 206b towards Second 6-State Magnet 203b (i.e., output magnet). In this case, the magnetic orientation of Second 6-State Magnet 203a (i.e., output magnet) is in -y direction (i.e., M=-y). In some embodiments, the input magnet 203a dictates the flow of the spin current in channel 206b. This is realized by the asymmetry of the magnet overlap with the channel. For example, First 6-State Magnet 203a overlaps more with channel 206b than Second 6-State Magnet 203b. [0094] In some embodiments, flow of spin current from First 6-State Magnet 203a to

Second 6-State Magnet 203b occurs comprising of spins with opposite polarity of First 6- State Magnet 203a. In some embodiments, for an inverter, the direction of the injected spins is reverse of the magnet polarity. For example, the direction of majority spins in channel region 206c is in the -y direction while the direction of magnetization of First Magnet 203a is in the +y direction. In this example, the direction 1123 of majority spin in channel 206c is in -y direction. In some embodiments, the direction of spins in channel region 206b below the two magnets can be the same for an inverter. Here, the majority spins in channel 206c under Second Magnet 203b are spins 1103.

[0095] Fig. 11B illustrates cross-section 1120 of a 6-State inverting spin gate injecting spins in the +y direction and receiving spins in the +y direction while the magnetizations of the first and second magnets are -y and +y, respectively, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Fig. 11B having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[0096] Here, spin current in the -y direction is injected in channel region 206a. The dominant spin current is shown by spin direction 1121 in the +y direction while some minority spin 1122 in channel 206a points in the -y direction. The propagation of the spin current through device 1120 depends on the magnetization of First and Second 6-State Magnets 203a/b.

[0097] In some embodiments, when a positive voltage (e.g., +Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 1120 behaves as an inverter. In this case, the magnetic orientation of First 6-State Magnet 203a (i.e., input magnet) is in -y direction (i.e., M=-y) causing the majority of spins to traverse through channel 206b towards Second 6-State Magnet 203b (i.e., output magnet). In this case, the magnetic orientation of Second 6-State Magnet 203a (i.e., output magnet) is in +y direction (i.e., M=+y). In some embodiments, the input magnet 203a dictates the flow of the spin current in channel 206b. This is realized by the asymmetry of the magnet overlap with the channel. For example, First 6-State Magnet 203a overlaps more with channel 206b than Second 6-State Magnet 203b.

[0098] In some embodiments, flow of spin current from First 6-State Magnet 203a to

Second 6-State Magnet 203b occurs comprising of spins with opposite polarity of First 6- State Magnet 203a. In some embodiments, for an inverter, the direction of the injected spins is reverse of the magnet polarity. For example, the direction of majority spins in channel region 206c is in the +y direction while the direction of magnetization of First Magnet 203a is in the -y direction. In this example, the direction 1123 of majority spin in channel 206c is in +y direction. In some embodiments, the direction of spins in channel region 206b below the two magnets can be the same for an inverter. Here, the majority spins in channel 206c under Second Magnet 203b are spins 1123.

[0099] Fig. 12A illustrates cross-section 1200 of a 6-State inverting spin gate injecting spins in the +z direction and receiving spins in the +z direction while the magnetizations of the first and second magnets are -z and +z, respectively, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Fig. 12A having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[00100] Here, spin current in the +z direction is injected in channel region 206a. The dominant spin current is shown by spin direction 1201 in the +z direction while some minority spin 1202 in channel 206a points in the -z direction. The propagation of the spin current through device 1200 depends on the magnetization of First and Second 6-State Magnets 203a/b.

[00101] In some embodiments, when a positive voltage (e.g., +Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 1200 behaves as an inverter. In this case, the magnetic orientation of First 6-State Magnet 203a (i.e., input magnet) is in -z direction (i.e., M=-z) causing the majority of spins to traverse through channel 206b towards Second 6-State Magnet 203b (i.e., output magnet). In this case, the magnetic orientation of Second 6-State Magnet 203a (i.e., output magnet) is in +z direction (i.e., M=+z). In some embodiments, the input magnet 203a dictates the flow of the spin current in channel 206b. This is realized by the asymmetry of the magnet overlap with the channel. For example, First 6-State Magnet 203a overlaps more with channel 206b than Second 6-State Magnet 203b.

[00102] In some embodiments, flow of spin current from First 6-State Magnet 203a to

Second 6-State Magnet 203b occurs comprising of spins with opposite polarity of First 6- State Magnet 203a. In some embodiments, for an inverter, the direction of the injected spins is reverse of the magnet polarity. For example, the direction of majority spins in channel region 206c is in the +z direction while the direction of magnetization of First Magnet 203a is in the -z direction. In this example, the direction 1203 of majority spin in channel 206c is in +z direction. In some embodiments, the direction of spins in channel region 206b below the two magnets can be the same for an inverter. Here, the majority spins in channel 206c under Second Magnet 203b are spins 1203.

[00103] Fig. 12B illustrates cross-section 1220 of a 6-State inverting spin gate injecting spins in the -z direction and receiving spins in the -z direction while the

magnetizations of the first and second magnets are +z and -z, respectively, in accordance with some embodiments of the disclosure. It is pointed out that those elements of Fig. 12A having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[00104] Here, spin current in the -z direction is injected in channel region 206a. The dominant spin current is shown by spin direction 1221 in the -z direction while some minority spin 1222 in channel 206a points in the +z direction. The propagation of the spin current through device 1220 depends on the magnetization of First and Second 6-State Magnets 203a/b.

[00105] In some embodiments, when a positive voltage (e.g., +Vdd) is applied to metal layer 201a and ground is applied to metal layer 201b, then device 1220 behaves as an inverter. In this case, the magnetic orientation of First 6-State Magnet 203a (i.e., input magnet) is in +z direction (i.e., M=+z) causing the majority of spins to traverse through channel 206b towards Second 6-State Magnet 203b (i.e., output magnet). In this case, the magnetic orientation of Second 6-State Magnet 203a (i.e., output magnet) is in -z direction (i.e., M=-z). In some embodiments, the input magnet 203a dictates the flow of the spin current in channel 206b. This is realized by the asymmetry of the magnet overlap with the channel. For example, First 6-State Magnet 203a overlaps more with channel 206b than Second 6-State Magnet 203b.

[00106] In some embodiments, flow of spin current from First 6-State Magnet 203a to

Second 6-State Magnet 203b occurs comprising of spins with opposite polarity of First 6- State Magnet 203a. In some embodiments, for an inverter, the direction of the injected spins is reverse of the magnet polarity for inverter. For example, the direction of majority spins in channel region 206c is in the -z direction while the direction of magnetization of First Magnet 203a is in the +z direction. In this example, the direction 1223 of majority spin in channel 206c is in -z direction. In some embodiments, the direction of spins in channel region 206b below the two magnets can be the same for an inverter.

[00107] The 6-State inverter operation can be described with reference to Table 1. In

Table 1, the power supply to metal layer 201a is a positive supply +Vdd. Table 1

[00108] The 6-State buffer operation can be described with reference to Table 2. In

Table 2, the power supply to metal layer 201a is a negative supply -Vdd.

Table 2

[00109] Fig. 13 illustrates spin logic device 1300 with 6-State magnet(s), according to some embodiments of the disclosure. It is pointed out that those elements of Fig. 13 having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such. Spin logic device 1300 is similar to spin logic device 500 except that an interface templating layer 522 (e.g., Ag) is deposited over metal layer 201a.

[00110] Fig. 14 illustrates flowchart 1400 of a method for fabricating a spin logic device with 6-state magnet (e.g., a non-exact upside down version of spin logic device 200 which is illustrated as spin logic device 1300), according to some embodiments of the disclosure. It is pointed out that those elements of Fig. 14 having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[00111] Although the blocks in the flowchart with reference to Fig. 14 are shown in a particular order, the order of the actions can be modified. Thus, the illustrated embodiments can be performed in a different order, and some actions/blocks may be performed in parallel. Some of the blocks and/or operations listed in Fig. 14 are optional in accordance with certain embodiments. The numbering of the blocks presented is for the sake of clarity and is not intended to prescribe an order of operations in which the various blocks must occur.

Additionally, operations from the various flows may be utilized in a variety of combinations. [00112] At block 1401, first metal layer 201a is deposited. In some embodiments, first metal layer 201a is coupled to supply (either Vdd or -Vdd). At block 1402, a first interface layer 522 is deposited over first metal layer 201a. In some embodiments, first interface layer 522 is formed of a non-magnetic material (e.g., Ag). At block 1403, a 6-State magnet layer 203 (e.g., before being etched to form input and output magnets 203 a/b) is deposited over first interface layer 522. In some embodiments, 6-State magnet layer 203 is formed of a material with a sufficiently high anisotropy and sufficiently low magnetic saturation to increase injection of spin currents.

[00113] At block 1404, a second interface layer 504 (before being etched to form first and second interface layers 504a/b) is deposited over 6-State magnet layer 203 such that 6- State magnet layer 203 is sandwiched between the first and second interface layers. In some embodiments, the first and second interface layers 522 and 504, respectively, are formed of non-magnetic material such that the interface layers and magnet layers 203 together have sufficiently matched atomistic crystalline layers.

[00114] In some embodiments, the processes of blocks 1401, 1402, 1403, and 1404 are performed in situ (i.e., the fabrication processes do not break vacuum). As such oxidization between interfaces of the layers 201, 522, 203, and 504 is avoided (i.e., smooth interface surfaces are achieved). Smooth interface surfaces of the layers 201, 522, 203, and 504 allow for higher spin injection efficiency, according to some embodiments.

[00115] In some embodiments, 6-State magnet layer 203 is patterned to form First and

Second 6-State Magnets 203a and 203b. This process breaks vacuum. For example, a photoresist material is deposited over second interface layer 504 and then etched for forming a patterned photo-resist layer, where the pattern indicates future locations of First and Second 6-State Magnets 203a/b. At block 1405, second interface layer 204 and 6-State magnet layer 203 are selectively etched using the patterned photo-resist to form first and second portions 204a/b of second interface layer 204. As such, First and Second 6-State Magnets 203a/b are also formed. The photo-resist material is then removed.

[00116] At block 1406, Spin Channel 206 (e.g., metal layer) is deposited over first and second portions 204a/b of second interface layer 504. In some embodiments, Spin Channel 206 is patterned into segments 206a/b/c by photo-resist deposition and patterning of the photo-resist material. At block 1407, portions of Spin Channel 206 are etched to form segments of Spin Channel 206/a/b/c. In some embodiments, the depth of etching of Spin Channel 206 is adjusted as discussed with reference to Fig. 4A. At block 1408, portions of Spin Channel 206 are etched above the first and second 6-state magnets. [00117] In some embodiments, at block 1409 the etched portions are filled with an insulator (e.g., Oxide 205b). In some embodiments, Oxide 205b is etched to form a via hole which is then filled with a metal to form Via 207 such that it couples Spin Channel 206b at one end of Via 207 as illustrated by block 1410. At block 1411, a second metal layer 201b is deposited over Oxide 205b to make contact with the other end of Via 207. In some embodiments, second metal layer 201b is coupled to a Power supply.

[00118] Fig. 15 illustrates a smart device or a computer system or a SoC (System-on-

Chip) 1600 with a spin logic device with 6-state magnet, according to some embodiments of the disclosure. Spin logic devices (e.g., devices 200-500) can be used for making high density embedded memory to improve performance of computer system. Spin logic devices (e.g., devices 200-500) an also be used to form non-volatile logic components to enable improved power and performance optimization. As such, battery life for the smart device of computer system can improve (i.e., last longer). It is pointed out that those elements of Fig. 15 having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described, but are not limited to such.

[00119] Fig. 15 illustrates a block diagram of an embodiment of a mobile device in which flat surface interface connectors could be used. In some embodiments, computing device 1600 represents a mobile computing device, such as a computing tablet, a mobile phone or smart-phone, a wireless-enabled e-reader, or other wireless mobile device. It will be understood that certain components are shown generally, and not all components of such a device are shown in computing device 1600.

[00120] For purposes of the embodiments, the transistors in various circuits and logic blocks described here are metal oxide semiconductor (MOS) transistors, which include drain, source, gate, and bulk terminals. The transistors also include Tri-Gate and FinFET transistors, Gate All Around Cylindrical Transistors, Tunneling FET (TFET), Square Wire, or Rectangular Ribbon Transistors or other devices implementing transistor functionality like carbon nanotubes or spintronic devices. MOSFET symmetrical source and drain terminals i.e., are identical terminals and are interchangeably used here. A TFET device, on the other hand, has asymmetric Source and Drain terminals. Those skilled in the art will appreciate that other transistors, for example, Bi-polar junction transistors— BJT PNP/NPN, BiCMOS, CMOS, eFET, etc., may be used without departing from the scope of the disclosure.

[00121] In some embodiments, computing device 1600 includes first processor 1610 with a spin logic device (e.g., devices 200/300/400/500/1300) with stacking of magnets below a spin channel and with matched spacer for improved spin injection, according to some embodiments discussed. Other blocks of the computing device 1600 may also include a spin logic device with stacking of magnets below a spin channel and with matched spacer for improved spin injection, according to some embodiments. The various embodiments of the present disclosure may also comprise a network interface within 1670 such as a wireless interface so that a system embodiment may be incorporated into a wireless device, for example, cell phone or personal digital assistant.

[00122] In some embodiments, processor 1610 can include one or more physical devices, such as microprocessors, application processors, microcontrollers, programmable logic devices, or other processing means. The processing operations performed by processor 1610 include the execution of an operating platform or operating system on which applications and/or device functions are executed. The processing operations include operations related to I/O (input/output) with a human user or with other devices, operations related to power management, and/or operations related to connecting the computing device 1600 to another device. The processing operations may also include operations related to audio I/O and/or display I/O.

[00123] In some embodiments, computing device 1600 includes audio subsystem

1620, which represents hardware (e.g., audio hardware and audio circuits) and software (e.g., drivers, codecs) components associated with providing audio functions to the computing device. Audio functions can include speaker and/or headphone output, as well as microphone input. Devices for such functions can be integrated into computing device 1600, or connected to the computing device 1600. In one embodiment, a user interacts with the computing device 1600 by providing audio commands that are received and processed by processor 1610.

[00124] In some embodiments, computing device 1600 comprises display subsystem

1630. Display subsystem 1630 represents hardware (e.g., display devices) and software (e.g., drivers) components that provide a visual and/or tactile display for a user to interact with the computing device 1600. Display subsystem 1630 includes display interface 1632, which includes the particular screen or hardware device used to provide a display to a user. In one embodiment, display interface 1632 includes logic separate from processor 1610 to perform at least some processing related to the display. In one embodiment, display subsystem 1630 includes a touch screen (or touch pad) device that provides both output and input to a user.

[00125] In some embodiments, computing device 1600 comprises I/O controller 1640.

I/O controller 1640 represents hardware devices and software components related to interaction with a user. I/O controller 1640 is operable to manage hardware that is part of audio subsystem 1620 and/or display subsystem 1630. Additionally, I/O controller 1640 illustrates a connection point for additional devices that connect to computing device 1600 through which a user might interact with the system. For example, devices that can be attached to the computing device 1600 might include microphone devices, speaker or stereo systems, video systems or other display devices, keyboard or keypad devices, or other I/O devices for use with specific applications such as card readers or other devices.

[00126] As mentioned above, I/O controller 1640 can interact with audio subsystem

1620 and/or display subsystem 1630. For example, input through a microphone or other audio device can provide input or commands for one or more applications or functions of the computing device 1600. Additionally, audio output can be provided instead of, or in addition to display output. In another example, if display subsystem 1630 includes a touch screen, the display device also acts as an input device, which can be at least partially managed by I/O controller 1640. There can also be additional buttons or switches on the computing device 1600 to provide I/O functions managed by I/O controller 1640.

[00127] In some embodiments, I/O controller 1640 manages devices such as accelerometers, cameras, light sensors or other environmental sensors, or other hardware that can be included in the computing device 1600. The input can be part of direct user interaction, as well as providing environmental input to the system to influence its operations (such as filtering for noise, adjusting displays for brightness detection, applying a flash for a camera, or other features).

[00128] In some embodiments, computing device 1600 includes power management

1650 that manages battery power usage, charging of the battery, and features related to power saving operation. Memory subsystem 1660 includes memory devices for storing information in computing device 1600. Memory can include nonvolatile (state does not change if power to the memory device is interrupted) and/or volatile (state is indeterminate if power to the memory device is interrupted) memory devices. Memory subsystem 1660 can store application data, user data, music, photos, documents, or other data, as well as system data (whether long-term or temporary) related to the execution of the applications and functions of the computing device 1600.

[00129] Elements of embodiments are also provided as a machine-readable medium (e.g., memory 1660) for storing the computer-executable instructions (e.g., instructions to implement any other processes discussed herein). The machine-readable medium (e.g., memory 1660) may include, but is not limited to, flash memory, optical disks, CD-ROMs, DVD ROMs, RAMs, EPROMs, EEPROMs, magnetic or optical cards, phase change memory (PCM), or other types of machine-readable media suitable for storing electronic or computer- executable instructions. For example, embodiments of the disclosure may be downloaded as a computer program (e.g., BIOS) which may be transferred from a remote computer (e.g., a server) to a requesting computer (e.g., a client) by way of data signals via a communication link (e.g., a modem or network connection).

[00130] In some embodiments, computing device 1600 comprises connectivity 1670.

Connectivity 1670 includes hardware devices (e.g., wireless and/or wired connectors and communication hardware) and software components (e.g., drivers, protocol stacks) to enable the computing device 1600 to communicate with external devices. The computing device 1600 could be separate devices, such as other computing devices, wireless access points or base stations, as well as peripherals such as headsets, printers, or other devices.

[00131] Connectivity 1670 can include multiple different types of connectivity. To generalize, the computing device 1600 is illustrated with cellular connectivity 1672 and wireless connectivity 1674. Cellular connectivity 1672 refers generally to cellular network connectivity provided by wireless carriers, such as provided via GSM (global system for mobile communications) or variations or derivatives, CDMA (code division multiple access) or variations or derivatives, TDM (time division multiplexing) or variations or derivatives, or other cellular service standards. Wireless connectivity (or wireless interface) 1674 refers to wireless connectivity that is not cellular, and can include personal area networks (such as Bluetooth, Near Field, etc.), local area networks (such as Wi-Fi), and/or wide area networks (such as WiMax), or other wireless communication.

[00132] In some embodiments, computing device 1600 comprises peripheral connections 1680. Peripheral connections 1680 include hardware interfaces and connectors, as well as software components (e.g., drivers, protocol stacks) to make peripheral connections. It will be understood that the computing device 1600 could both be a peripheral device ("to" 1682) to other computing devices, as well as have peripheral devices ("from" 1684) connected to it. The computing device 1600 commonly has a "docking" connector to connect to other computing devices for purposes such as managing (e.g., downloading and/or uploading, changing, synchronizing) content on computing device 1600. Additionally, a docking connector can allow computing device 1600 to connect to certain peripherals that allow the computing device 1600 to control content output, for example, to audiovisual or other systems.

[00133] In addition to a proprietary docking connector or other proprietary connection hardware, the computing device 1600 can make peripheral connections 1680 via common or standards-based connectors. Common types can include a Universal Serial Bus (USB) connector (which can include any of a number of different hardware interfaces), DisplayPort including MiniDisplayPort (MDP), High Definition Multimedia Interface (HDMI), Firewire, or other types.

[00134] Reference in the specification to "an embodiment," "one embodiment," "some embodiments," or "other embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments. The various appearances of "an embodiment," "one embodiment," or "some embodiments" are not necessarily all referring to the same embodiments. If the specification states a component, feature, structure, or characteristic "may," "might," or "could" be included, that particular component, feature, structure, or characteristic is not required to be included. If the specification or claim refers to "a" or "an" element, that does not mean there is only one of the elements. If the specification or claims refer to "an additional" element, that does not preclude there being more than one of the additional element.

[00135] Furthermore, the particular features, structures, functions, or characteristics may be combined in any suitable manner in one or more embodiments. For example, a first embodiment may be combined with a second embodiment anywhere the particular features, structures, functions, or characteristics associated with the two embodiments are not mutually exclusive.

[00136] While the disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of such embodiments will be apparent to those of ordinary skill in the art in light of the foregoing description. The embodiments of the disclosure are intended to embrace all such alternatives, modifications, and variations as to fall within the broad scope of the appended claims.

[00137] In addition, well known power/ground connections to integrated circuit (IC) chips and other components may or may not be shown within the presented figures, for simplicity of illustration and discussion, and so as not to obscure the disclosure. Further, arrangements may be shown in block diagram form in order to avoid obscuring the disclosure, and also in view of the fact that specifics with respect to implementation of such block diagram arrangements are highly dependent upon the platform within which the present disclosure is to be implemented (i.e., such specifics should be well within purview of one skilled in the art). Where specific details (e.g., circuits) are set forth in order to describe example embodiments of the disclosure, it should be apparent to one skilled in the art that the disclosure can be practiced without, or with variation of, these specific details. The description is thus to be regarded as illustrative instead of limiting.

[00138] The following examples pertain to further embodiments. Specifics in the examples may be used anywhere in one or more embodiments. All optional features of the apparatus described herein may also be implemented with respect to a method or process.

[00139] For example, an apparatus is provided which comprises: input and output magnets, each configured to have six stable magnetic states including zero state, first state, second state, third state, fourth state, and fifth state, wherein the zero state is to point in a +x- direction, wherein the first state is to point in a +y-direction, wherein the second state is to point in a -y-direction, wherein the third state is to point in a -x-direction, wherein the fourth state is to point in a -z-direction, and wherein the fifth state is to point in a +z-direction. In some embodiments, the input and output magnets are one of: magnetostrictive ferromagnets adjacent to corresponding piezoelectric layers; tri-axial anisotropy magnets; or in-plane biaxial anisotropy magnets adjacent to corresponding piezoelectric layers.

[00140] In some embodiments, a thermal barrier between the zero, first, second, third, fourth, and fifth states is greater than or equal to 10 kT. In some embodiments, the apparatus comprises: a first spin channel region adjacent to the input magnet; a second spin channel region adjacent to the input and output magnets; and a third spin channel region adj acent to the output magnet. In some embodiments, the input and output magnets are formed of a material selected from a group consisting of: Fe, Ni, Co and their alloys, magnetic insulators, and Heusler alloys of the form X2YZ.

[00141] In some embodiments, the magnetic insulators are formed of a material selected from a group consisting of: magnetite Fe₃0₄ and Y3AI5O12. In some embodiments, the Heusler alloys is one of: Co₂FeSi and M Ga. In some embodiments, the first, second, and third spin channel regions are formed of a material selected from a group consisting of: Cu, Ag, Al, and 2D conducting materials. In some embodiments, the 2D conducting materials are selected from a group consisting of: graphene, M0S2, MoSe, WS, and WSe.

[00142] In some embodiments, the apparatus comprises: a first oxide region separating at least a portion of the first spin channel region from the second spin channel region; and a second oxide region separating at least a portion the second spin channel region from the third spin channel region. In some embodiments, a portion of the first spin channel region is adjacent to a portion of the second spin channel region, and wherein a portion of the second spin channel region is adjacent to a portion of the third spin channel region. In some embodiments, the apparatus comprises a third oxide region separating the input magnet from the output magnet.

[00143] In some embodiments, the apparatus comprises a non-magnetic metal adjacent to the input magnet and the output magnet. In some embodiments, the non-magnetic metal is coupled to a positive supply to configure the apparatus as a buffer. In some embodiments, the non-magnetic metal is coupled to a negative supply to configure the apparatus as an inverter.

[00144] In another example, a system is provided which comprises: a memory; a processor coupled to the memory, the processor including an apparatus according to the apparatus described above; and a wireless interface for allowing the processor to

communicate with another device.

[00145] In another example, an apparatus is provided which comprises: a tri-axial anisotropy input magnet; a first spin channel region adjacent to the tri-axial anisotropy input magnet; a tri-axial anisotropy output magnet; a second spin channel region adjacent to the tri- axial anisotropy input and output magnets; and a third spin channel region adjacent to the tri- axial anisotropy output magnet. In some embodiments, the input magnet is the tri-axial anisotropy input magnet, and wherein the output magnet is the tri-axial anisotropy output magnet.

[00146] In some embodiments, the apparatus comprises: a first spin channel region adjacent to the input magnet; a second spin channel region adjacent to the input and output magnets; and a third spin channel region adjacent to the output magnet. In some

embodiments, the input and output magnets are formed of a material selected from a group consisting of: Fe, Ni, Co and their alloys, magnetic insulators, and Heusler alloys of the form X₂YZ.

[00147] In some embodiments, the magnetic insulators are formed of a material selected from a group consisting of: magnetite Fe₃0₄ and Y3AI5O12. In some embodiments, the Heusler alloys is one of: Co₂FeSi and M Ga. In some embodiments, the first, second, and third spin channel regions are formed of a material selected from a group consisting of: Cu, Ag, Al, and 2D conducting materials. In some embodiments, the 2D conducting materials are selected from a group consisting of: graphene, M0S2, MoSe, WS, and WSe.

[00148] In some embodiments, the apparatus comprises: a first oxide region separating at least a portion of the first spin channel region from the second spin channel region; and a second oxide region separating at least a portion the second spin channel region from the third spin channel region. In some embodiments, a portion of the first spin channel region is adjacent to a portion of the second spin channel region, and wherein a portion of the second spin channel region is adjacent to a portion of the third spin channel region. In some embodiments, the apparatus comprises a third oxide region separating the input magnet from the output magnet.

[00149] In some embodiments, the apparatus comprises a non-magnetic metal adjacent to the input magnet and the output magnet. In some embodiments, the non-magnetic metal is coupled to a positive supply to configure the apparatus as a buffer. In some embodiments, the non-magnetic metal is coupled to a negative supply to configure the apparatus as an inverter.

[00150] In some embodiments, the apparatus comprises: a via adjacent to the second spin channel region; and a non-magnetic metal adjacent to via. In some embodiments, the tri- axial anisotropy input and output magnets have cubic magnetic crystalline anisotropy. In some embodiments, the tri-axial anisotropy input magnet overlaps the second spin channel region more than the tri-axial anisotropy output magnet overlaps the second spin channel region.

[00151] In another example, a system is provided which comprises: a memory; a processor coupled to the memory, the processor including an apparatus according to the apparatus described above; and a wireless interface for allowing the processor to

communicate with another device.

[00152] In another example, an apparatus is provided which comprises: a tri-axial anisotropy input magnet; a first filter layer adjacent to the tri-axial anisotropy input magnet; a first spin channel region adjacent to the first filter layer; a tri-axial anisotropy output magnet; a second filter layer adjacent to the tri-axial anisotropy output magnet; a second spin channel region adjacent to the first and second filter layers; and a third spin channel region adjacent to the second filter layer. In some embodiments, the input magnet is the tri-axial anisotropy input magnet, and wherein the output magnet is the tri-axial anisotropy output magnet.

[00153] In some embodiments, the apparatus comprises: a first spin channel region adjacent to the input magnet; a second spin channel region adjacent to the input and output magnets; and a third spin channel region adjacent to the output magnet. In some

embodiments, the input and output magnets are formed of a material selected from a group consisting of: Fe, Ni, Co and their alloys, magnetic insulators. andHeusler alloys of the form X -'VZ.

[00154] In some embodiments, the magnetic insulators are formed of a material selected from a group consisting of: magnetite Fe₃0₄ and Y3AI5O12. In some embodiments, the Heusler alloys is one of: Co₂FeSi and M Ga. In some embodiments, the first, second, and third spin channel regions are formed of a material selected from a group consisting of: Cu, Ag, Al, and 2D conducting materials. In some embodiments, the 2D conducting materials are selected from a group consisting of: graphene, M0S2, MoSe, WS, and WSe.

[00155] In some embodiments, the apparatus comprises: a first oxide region separating at least a portion of the first spin channel region from the second spin channel region; and a second oxide region separating at least a portion the second spin channel region from the third spin channel region. In some embodiments, a portion of the first spin channel region is adjacent to a portion of the second spin channel region, and wherein a portion of the second spin channel region is adjacent to a portion of the third spin channel region. In some embodiments, the apparatus comprises a third oxide region separating the input magnet from the output magnet.

[00156] In some embodiments, the apparatus comprises a non-magnetic metal adjacent to the input magnet and the output magnet. In some embodiments, the non-magnetic metal is coupled to a positive supply to configure the apparatus as a buffer. In some embodiments, the non-magnetic metal is coupled to a negative supply to configure the apparatus as an inverter.

[00157] In some embodiments, the first and second filter layers are formed of a material selected from a group consisting of: MgO, AI2O3, BN, MgAl₂04, ZnAh04,

SiMg204, and SiZ C , and NiFeO. In some embodiments, the tri-axial anisotropy input magnet and the first filter layer overlap the second spin channel region more than the tri-axial anisotropy output magnet and second filter layer overlap the second spin channel region.

[00158] In another example, a system is provided which comprises: a memory; a processor coupled to the memory, the processor including an apparatus according to the apparatus described above; and a wireless interface for allowing the processor to

communicate with another device.

[00159] In another example, a system is provided which comprises: a memory; a processor coupled to the memory, the processor including an apparatus according to the apparatus described above; and a wireless interface for allowing the processor to

communicate with another device.

[00160] In another example, a method is provided which comprises: depositing a first metal layer; depositing a first interface layer on the first metal layer, the first interface layer formed of a mon-magnetic material; and depositing a 6-state magnet layer over the first interface layer. In some embodiments, the method comprises depositing a second interface layer once the 6-state magnet layer. In some embodiments, depositing of the first metal layer, first interface layer, 6-state magnet layer, and second interface layer is performed in situ. In some embodiments, the method comprises depositing a photo-resist material over the second interface layer to pattern the first and second 6-state magnets.

[00161] In some embodiments, the method comprises etching the second interface layer and the 6-state magnet layer to form first and second portions of the second interface layer over the first and second 6-state magnets, respectively. In some embodiments, the method comprises depositing a spin channel over the first and second portions of the second interface layer. In some embodiments, the method comprises etching portions of the spin channel above the first and second 4-state magnets. In some embodiments, the method comprises filling the etched portions with an insulator to provide barriers between portions of the spin channel. In some embodiments, the method comprises forming a via such that it couples the spin channel at one end of the via. In some embodiments, the method comprises depositing a second metal layer over the via at the other end of the via.

[00162] An abstract is provided that will allow the reader to ascertain the nature and gist of the technical disclosure. The abstract is submitted with the understanding that it will not be used to limit the scope or meaning of the claims. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.

Claims

CLAIMS We claim:

1. An apparatus comprising:

input and output magnets, each configured to have six stable magnetic states including zero state, first state, second state, third state, fourth state, and fifth state,

wherein the zero state is to point in a +x-direction,

wherein the first state is to point in a +y-direction,

wherein the second state is to point in a -y-direction,

wherein the third state is to point in a -x-direction,

wherein the fourth state is to point in a -z-direction, and

wherein the fifth state is to point in a +z-direction.

2. The apparatus of claim 1 , wherein the input and output magnets are one of:

magnetostrictive ferromagnets adjacent to corresponding piezoelectric layers;

tri-axial anisotropy magnets; or

in-plane bi-axial anisotropy magnets adjacent to corresponding piezoelectric layers.

3. The apparatus of claim 1 , wherein a thermal barrier between the zero, first, second, third, fourth, and fifth states is greater than or equal to 10 kT.

4. The apparatus of claim 3 comprises:

a first spin channel region adjacent to the input magnet;

a second spin channel region adjacent to the input and output magnets; and a third spin channel region adjacent to the output magnet.

5. The apparatus of claim 4, wherein the input and output magnets are formed of a material selected from a group consisting of: Fe, Ni, Co and their alloys, magnetic insulators, and Heusler alloys of the form X? YZ.

6. The apparatus of claim 5, wherein the magnetic insulators are formed of a material

selected from a group consisting of: magnetite Fe₃0₄ and Y3AI5O12.

7. The apparatus of claim 6, wherein the Heusler alloys is one of: Co₂FeSi and MmGa.

8. The apparatus of claim 4, wherein the first, second, and third spin channel regions are formed of a material selected from a group consisting of: Cu, Ag, Al, and 2D conducting materials.

9. The apparatus of claim 8, wherein the 2D conducting materials are selected from a group consisting of: graphene, M0S2, MoSe, WS, and WSe.

10. The apparatus of claim 4 comprises:

a first oxide region separating at least a portion of the first spin channel region from the second spin channel region; and

a second oxide region separating at least a portion the second spin channel region from the third spin channel region.

11. The apparatus of claim 10, wherein a portion of the first spin channel region is adjacent to a portion of the second spin channel region, and wherein a portion of the second spin channel region is adjacent to a portion of the third spin channel region.

12. The apparatus of claim 10 comprises a third oxide region separating the input magnet from the output magnet.

13. The apparatus of claim 4 comprises a non-magnetic metal adjacent to the input magnet and the output magnet.

14. The apparatus of claim 13, wherein the non- magnetic metal is coupled to a positive supply to configure the apparatus as a buffer.

15. The apparatus of claim 13, wherein the non-magnetic metal is coupled to a negative

supply to configure the apparatus as an inverter.

16. An apparatus comprising:

a tri-axial anisotropy input magnet;

a first spin channel region adjacent to the tri-axial anisotropy input magnet;

a tri-axial anisotropy output magnet; a second spin channel region adjacent to the tri-axial anisotropy input and output magnets; and

a third spin channel region adjacent to the tri-axial anisotropy output magnet.

17. The apparatus of claim 16, according to any one of claims 4 to 15, wherein the input magnet is the tri-axial anisotropy input magnet, and wherein the output magnet is the tri- axial anisotropy output magnet.

18. The apparatus of claim 16 comprises:

a via adjacent to the second spin channel region; and

a non-magnetic metal adjacent to via.

19. The apparatus of claim 16, wherein the tri-axial anisotropy input and output magnets have cubic magnetic crystalline anisotropy.

20. The apparatus of claim 16, wherein the tri-axial anisotropy input magnet overlaps the second spin channel region more than the tri-axial anisotropy output magnet overlaps the second spin channel region.

21. An apparatus comprising:

a tri-axial anisotropy input magnet;

a first filter layer adjacent to the tri-axial anisotropy input magnet;

a first spin channel region adjacent to the first filter layer;

a tri-axial anisotropy output magnet;

a second filter layer adjacent to the tri-axial anisotropy output magnet;

a second spin channel region adjacent to the first and second filter layers; and a third spin channel region adjacent to the second filter layer.

22. The apparatus of claim 21 according to any one of claims 4 to 15, wherein the input magnet is the tri-axial anisotropy input magnet, and wherein the output magnet is the tri- axial anisotropy output magnet.

23. The apparatus of claim 21, wherein the first and second filter layers are formed of a material selected from a group consisting of: MgO, AI2O3, BN, MgAl₂04, ZnAh04, SiMg₂0₄, and SiZn₂0₄, and NiFeO.

24. The apparatus of claim 21, wherein the tri-axial anisotropy input magnet and the first filter layer overlap the second spin channel region more than the tri-axial anisotropy output magnet and second filter layer overlap the second spin channel region.

25. A system comprising:

a memory;

a processor coupled to the memory, the processor including an apparatus according to any one of apparatus claims 1 to 15; and

a wireless interface for allowing the processor to communicate with another device.