JP2014022735A - Method and system for providing magnetic tunneling junctions usable in spin transfer torque magnetic memories - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide improved magnetic junctions usable in high-density STT-RAMs.SOLUTION: A method and system provide a magnetic junction. A free layer, a symmetry filter, and a pinned layer are provided. The free layer can have a magnetic moment switchable between stable magnetic states when a readout current passes through the magnetic junction. The symmetry filter transmits charge carriers having a first symmetry with higher probability than charge carriers having another symmetry. The symmetry filter may reside between the free layer and the pinned layer. The free layer and/or the pinned layer lies in a plane, has the charge carriers of the first symmetry in a spin channel at the Fermi level, lacks the charge carriers of the first symmetry at the Fermi level in another spin channel, and has a nonzero magnetic moment component perpendicular to the plane. The free layer and/or the pinned layer and the symmetry filter has at least one lattice mismatch of less than seven percent.

Description

  The present invention relates to a magnetic junction for a magnetic element such as a magnetic memory and an element using such a magnetic junction.

  Magnetic memories, especially magnetic random memories (MRAMs), are of increasing interest due to high read / write speeds, durability, non-volatility and the potential for low power consumption between drives. One type of MRAM is a spin transfer torque random access memory (STT-RAM). The STT-RAM utilizes a magnetic junction that is written at least in part by a current driven through the magnetic junction.

  FIG. 1 shows a conventional magnetic tunnel junction (MTJ) 10 using a conventional STT-RAM. A conventional MTJ 10 is generally above the conventional lower contact 11, uses a conventional seed layer 12, and is below the conventional upper contact 16. A conventional MTJ 10 includes a conventional antiferromagnetic (AFM) layer 20, a conventional pinned layer 30, a conventional tunnel barrier layer 40, and a conventional free layer 50. Also shown is a conventional capping layer 14. In contrast to the stabilization of the magnetic moment 32 of the conventional pinned layer 30, the conventional free layer 50 can have a variable magnetic moment 52. More specifically, the magnetic moment 32 of the pinned layer 30 can be pinned by interaction with a conventional antiferromagnetic (AFM) layer 20.

  Conventional contacts 12, 16 can be used to drive current in the plane normal current (CPP) direction or the z-axis direction as shown in FIG. The current passing through the conventional fixed layer 30 is spin-polarized and can transmit angular momentum. The angular momentum can be transmitted to the conventional free layer 50. If a sufficient amount of angular momentum is transmitted, the magnetic moment 52 of the free layer 50 can be switched parallel or anti-parallel to the magnetic moment 32 of the pinned layer 30.

  It may be required that various elements of the conventional magnetic junction 10 be optimized to improve the performance of the STT-RAM. For example, the conventional magnetic junction 10 can be designed to obtain the desired critical current Ic for switching the thermally stable conventional free layer 50. The critical current can be calculated by the following equation:

Here, <H> _eff is an average effective magnetic field that appears due to the precessing magnetic moment of the conventional free layer 50, and H _k switches the magnetic moment 52 when the magnetic field is applied to the easy axis. Is the required magnetic field, α is the damping parameter, and η is the spin torque efficiency. 1.5 mA indicates current and is approximated by a thermal stability factor of 60 (ΔE / k _B T). Here, ΔE is an energy barrier necessary for thermal switching, k _B is a Boltzmann constant, and T is an absolute temperature.

  The conventional magnetic junction 10 can be optimized to improve the critical current. Conventional magnetic junction 10 designs can include using CoFe and / or CoFeB for the conventional pinned layer 30 and the conventional free layer 50. CoFe and CoFeB tend to have in-plane magnetic moments, as indicated by magnetic moments 32,52. In addition, the conventional tunnel barrier layer 40 may be crystalline MgO. The combination of MgO and CoFe and CoFeB can provide a low critical current.

  Even though the conventional magnetic tunnel junction 10 can function, additional improvements may be required. For example, with a magnetic junction for a magnetic memory, the magnetic memory can be reduced to a smaller size, a smaller critical current can be used, the magnetic junction is easier to manufacture, and / or It may be required to have other properties.

  One technical problem to be solved by the present invention is to provide an improved magnetic junction that can be used in high density STT-RAM.

  A magnetic junction, a magnetic junction for a magnetic memory element, a magnetic memory, and a method for manufacturing a magnetic junction for a magnetic memory element are provided. A magnetic junction according to the inventive concept comprises a free layer having a first magnetic moment that is switchable between a plurality of stable magnetic states when a write current passes through the magnetic junction, and a charge carrier having a second symmetry. A symmetric filter for transmitting charge carriers having a first symmetry with a higher probability and a pinned layer having a second magnetic moment fixed in one direction, wherein the symmetric filter includes the free layer and the pinned layer. And at least one of the pinned layer and the free layer has the first symmetric charge carrier at a Fermi level in one spin channel and a Fermi level in another spin channel. The first symmetric charge carrier at the position is depleted, has a non-zero magnetic moment element disposed in-plane and perpendicular to the plane, and And Luther, at least one among the fixed layer and the free layer may have a low lattice mismatch than 7 percent between.

  According to one embodiment, the lattice mismatch can be lower than 4 percent.

  According to an embodiment, at least one of the free layer and the pinned layer may include AlMn.

  According to one embodiment, the symmetric filter can include at least one of Ge, GaAs, and ZnSe.

  According to an embodiment, the first magnetic moment may be perpendicular to the plane.

  According to one embodiment, the second magnetic moment may be perpendicular to the plane.

  According to one embodiment, at least one of the free layer and the pinned layer may include at least one of MnGa and MnIn.

  According to one embodiment, the symmetric filter may be a tunnel barrier layer.

  According to one embodiment, at least one of the free layer and the pinned layer may be a synthetic diamagnetic material.

  According to an embodiment, a spacer layer and an additional pinned layer are further included, the spacer layer being interposed between the free layer and the additional pinned layer, and the additional pinned layer. The layer can have a third magnetic moment.

  According to one embodiment, the additional pinned layer may include AlMn.

  According to one embodiment, the spacer layer may be an additional symmetric filter.

  According to one embodiment, having an additional lattice mismatch of less than 7 percent between the additional symmetric filter and at least one of the free layer and the additional pinned layer. it can.

  According to one embodiment, the additional lattice mismatch can be lower than 4 percent.

  According to one embodiment, the additional symmetric filter can include at least one of Ge, GaAs, and ZnSe.

  According to an embodiment, the free layer, the pinned layer, and the additional pinned layer may be a synthetic antiferromagnetic material.

  A magnetic junction for a magnetic memory device in accordance with the concept of the present invention comprises AlMn having a (001) axis that is parallel to the plane and perpendicular to the plane, and when the write current passes through the magnetic junction, Having a first magnetic moment that is switched between magnetic states, having a first symmetric charge carrier at the Fermi level in a first number of spin channels, and having a first number of spin channels in the first number of spin channels. A symmetric charge carrier is depleted, the first magnetic moment transmits a free layer having a first non-zero element perpendicular to the plane, the charge carrier having the first symmetry, and the first symmetry; A symmetric filter that attenuates the charge carriers having different second symmetry and includes at least one of Ge, GaAs, and ZnSe, and is parallel to the plane and perpendicular to the plane A second non-zero element perpendicular to the plane, having a second magnetic moment fixed in one direction, and having a second magnetic moment in a second multiple spin channel A pinned layer having the first symmetric charge carriers at the Fermi level and depleted of the first symmetric charge carriers in a second minority spin channel;

  The symmetric filter may be interposed between the free layer and the fixed layer.

  A magnetic memory according to the inventive concept includes at least one select element and at least one magnetic junction, the at least one magnetic junction being between a free layer, a pinned layer, and the free layer and the pinned layer. An intervening symmetrical filter, wherein the free layer has a first magnetic moment that switches between a plurality of stable magnetic states when a write current passes through the magnetic junction, the symmetrical filter having a first symmetry. Transmitting charge carriers having a higher probability than the charge carriers having a second symmetry, wherein the pinned layer has a second magnetic moment pinned in one direction, at least of the free layer and the pinned layer. One has the first symmetric charge carrier at the Fermi level in the first spin channel and the Fermi level in the second spin channel. The first symmetric charge carrier is depleted, has a non-zero magnetic moment element disposed in-plane and perpendicular to the plane, and at least one of the symmetric filter, the free layer and the pinned layer A plurality of magnetic storage cells having a lattice mismatch lower than 7 percent, a plurality of bit lines coupled to the plurality of magnetic storage cells, and a plurality of word lines coupled to the plurality of magnetic storage cells And can be included.

  According to one embodiment, the lattice mismatch can be lower than 4 percent.

  According to one embodiment, the symmetric filter can include at least one of Ge, GaAs, and ZnSe.

  A magnetic junction for a magnetic memory element in accordance with the concept of the present invention is parallel to a plane and has a first magnetic moment that switches between a plurality of stable magnetic states when a read current passes through the magnetic junction. A free layer having a first non-zero element that is perpendicular to the plane; a pinned layer having a second magnetic moment parallel to the plane and fixed in one direction; the free layer and the pinned A symmetric filter interposed between the layers, wherein the second magnetic moment has a second non-zero element that is perpendicular to the plane, and at least one of the free layer and the pinned layer is Having a first symmetric charge carrier at Fermi energy in a first majority of spin channels, depleting the first symmetric charge carrier in a first few spin channels, The charge carrier having a first symmetry is transmitted, the charge carrier having a second symmetry different from the first symmetry is attenuated, and the symmetric filter and at least one of the free layer and the pinned layer are 7 It can have a lattice mismatch lower than a percentage.

  A magnetic junction for a magnetic memory element in accordance with the concepts of the present invention is parallel to a plane and has a first magnetic moment that switches between a plurality of stable magnetic states when a read current passes through, and a first majority. Having a first symmetric charge carrier at the Fermi level in the first spin channel, the first symmetric charge carrier being depleted in the first few spin channels, and the first magnetic moment being perpendicular to the plane Parallel to the plane, a free layer having a first non-zero element, a symmetric filter for transmitting charge carriers having the first symmetry and attenuating charge carriers having a second symmetry different from the first symmetry; , Having a second magnetic moment fixed in one direction, having the first symmetric charge carrier at the Fermi level in a second multiple spin channel, and a second minority The pinned channel is depleted of the first symmetric charge carriers, and the second magnetic moment includes a pinned layer having a second non-zero element perpendicular to the plane, the symmetric filter comprising the pinned layer and Intervening between the free layers, the symmetric filter and at least one of the free layer and the pinned layer may have a lattice mismatch of less than 7 percent.

  A method of manufacturing a magnetic junction for a magnetic memory device in accordance with the concepts of the present invention provides a magnetic junction stack including a free layer film, a fixed layer film, and a symmetric filter film, wherein the symmetric filter film has a first symmetric charge. Transmitting a carrier, attenuating the charge carrier having a second symmetry, interposed between the free layer film and the fixed layer film, wherein at least one of the fixed layer film and the free layer film is The first symmetric charge carriers at the Fermi level in one spin channel and the first symmetric charge carriers at the Fermi level in another spin channel are depleted and placed in-plane, The symmetric filter and at least one of the free layer and the pinned layer have a lattice mismatch of less than 7 percent. A free layer defined from the free layer film, a symmetric filter defined from the symmetric filter film, and a pinned layer defined from the pinned layer film, wherein the free layer has a first magnetic moment. The pinned layer includes defining a magnetic junction having a second magnetic moment, and setting the second magnetic moment of the pinned layer fixed in a specific direction. The first magnetic moment can be configured to switch between a plurality of stable magnetic states when a read current passes through the magnetic junction.

  According to one embodiment, the lattice mismatch can be lower than 4 percent.

  According to an embodiment, at least one of the free layer film and the fixed layer film may include AlMn disposed in the plane and having a (001) axis perpendicular to the plane. .

  According to one embodiment, the symmetric filter can include at least one of Ge, GaAs, and ZnSe.

  According to one embodiment, providing the magnetic junction stack includes forming a spacer layer film and forming an additional pinned film for an additional pinned layer, the spacer Is interposed between the additional pinned layer film and the free layer film, and the additional pinned layer may have the third magnetic moment.

In the magnetic junction according to the concept of the present invention, the magnetic moment of the free layer and the fixed layer is perpendicular to the plane, and the <H> _eff / H _k value may be 1. The spin polarization efficiency can be improved and the performance of the magnetic junction can be increased. Magnetic memories and magnetic elements including magnetic junctions according to the present invention can exhibit improved performance.

1 shows a conventional magnetic tunnel junction. 2 illustrates an exemplary embodiment of a magnetic junction for a magnetic memory. FIG. 6 illustrates an exemplary embodiment of a band structure for a majority and minority spin channel with a free layer and / or a pinned layer according to one embodiment of a magnetic junction. 6 illustrates an exemplary embodiment showing transmission of charge carriers through a symmetric filter based on wave function symmetry. FIG. 6 illustrates another exemplary embodiment of a magnetic junction for a magnetic memory in which the free layer and the fixed layer have a state with Fermi energy having symmetry that is preferentially transmitted by the spin filter layer. 3 illustrates another exemplary embodiment of a magnetic junction for a magnetic memory. 3 illustrates another exemplary embodiment of a magnetic junction for a magnetic memory. 3 illustrates another exemplary embodiment of a magnetic junction for a magnetic memory. 3 illustrates another exemplary embodiment of a magnetic junction for a magnetic memory. 3 illustrates another exemplary embodiment of a magnetic junction for a magnetic memory. Fig. 3 illustrates another exemplary embodiment of a heterogeneous magnetic junction for a magnetic memory. 2 illustrates an exemplary embodiment of a magnetic memory that uses magnetic junctions. 2 illustrates an exemplary embodiment of a method for manufacturing a magnetic tunnel junction for a magnetic memory.

  This invention was made with US government support under the registration / contract number HR0011-09-C-0023 awarded by DARPA. The US government has certain rights to the invention. Equity is authorized only by the US government.

  Exemplary embodiments of the present invention relate to a magnetic junction for a magnetic element such as a magnetic memory and to an element using this magnetic junction. The following description provides content relating to the present patent application and what is needed for it to be made and used by those skilled in the art. Various modifications to the exemplary embodiments and general principles and characteristics described herein can be readily made possible. Exemplary embodiments are primarily described in terms of the methods and systems provided in the specific examples. However, the method and system of the present invention works effectively with other embodiments. Terms such as “exemplary embodiment”, “one embodiment”, and “other embodiments” may mean the same or other embodiments, as well as multiple embodiments. Embodiments are disclosed with respect to systems and / or elements having certain elements. However, the system and / or elements of the present invention can include more or fewer elements than shown, and variations in the arrangement and type of these elements can be made within the scope of the present invention. Exemplary embodiments are described within the context of a particular method having predetermined steps. However, the methods and systems of the present invention are different in methods having different and / or additional steps, and in other orders not consistent with the exemplary embodiments, and in other methods having other and / or additional steps. It can implement effectively with respect to it. The present invention is not limited to the illustrated embodiments, but can correspond to the broadest scope consistent with the principles and characteristics described herein.

  A method and system for providing a magnetic junction is disclosed. The present system and system can include a free layer, a symmetric filter, and a pinned layer. The free layer can have a first magnetic moment that can switch between a number of stable magnetic states as the write current passes through the magnetic junction. Symmetric filters can pass charge carriers having a first symmetry with a higher probability than other charge carriers having a symmetry. The pinned layer may have a second magnetic moment fixed in a specific direction. A symmetric filter may be interposed between the free layer and the fixed layer. At least one of the free layer and the pinned layer has a first symmetric charge carrier at the Fermi level in one spin channel and a first symmetric charge carrier at the Fermi level in the other spin channel. Can be depleted, placed in a plane, and have a non-zero magnetic moment element that is substantially perpendicular to the plane. The free layer and / or pinned layer and the symmetric filter can have at least one lattice mismatch, but this lattice mismatch can be less than 7 percent. In other aspects, the at least one lattice mismatch can be less than 3 or 4 percent. In other aspects, the symmetric filter can include at least one of Ge, GaAs, and ZnSe.

  Exemplary embodiments of the present invention can be disclosed in connection with specific magnetic junctions and magnetic memories having predetermined elements. One skilled in the art can readily appreciate that the present invention applies to magnetic junctions and magnetic memories having other and / or additional elements and / or properties that are not consistent with the present invention. The method and system of the present invention can be disclosed in connection with the current understanding of the spin transfer phenomenon. Thus, those skilled in the art should readily understand that a theoretical explanation for the behavior of the method and system of the present invention is based on a current understanding of spin transfer. Those skilled in the art will also readily appreciate that the methods and systems of the present invention are disclosed in connection with structures having a particular relationship with the substrate. However, one of ordinary skill in the art should readily appreciate that the method and system of the present invention can be applied to other structures. Moreover, the method and system of the present invention can be disclosed in connection with certain layers that are synthetic and / or simple. However, those skilled in the art should readily understand that this layer has other structures. Moreover, the method and system can be disclosed for a magnetic junction having a particular layer. However, one of ordinary skill in the art will readily appreciate that magnetic junctions with additional and / or other layers not consistent with this method and system can be used. In addition, specific elements can be disclosed as magnetic, ferromagnetic, and ferrimagnetic. As used herein, the term “magnetic” can include ferromagnetic, ferrimagnetic, or similar structures. Accordingly, the term “magnetic” or “ferromagnetic” as used herein includes, but is not limited to, ferromagnets and ferrimagnets. The method and system of the present invention can be disclosed in connection with a single element. However, those skilled in the art will appreciate that the method and system of the present invention can be used in magnetic memories having multiple elements. Moreover, the term “in-plane” as used herein can mean substantially within one or more layers of the magnetic junction or parallel to the layers. Conversely, “perpendicular” can correspond to a direction that is substantially perpendicular to one or more layers of the magnetic junction.

  FIG. 2 illustrates an exemplary embodiment of the magnetic junction 100. For example, the magnetic junction 100 can be used in a magnetic memory, where current can be driven through the magnetic junction 100 in the CPP direction. FIG. 2 is not illustrated according to an actual scale, and a portion of the magnetic junction 100 may be omitted. The magnetic junction 100 can include a pinned layer 110, a spin filter 120, and a free layer 130. The magnetic junction 100 may include other layers (not shown).

  The free layer 130 may be a magnetic layer having a magnetic moment 131 that is variable. The magnetic moment 131 is illustrated as having arrows at both ends, indicating that the magnetic moment 131 can change direction. When the write current passes through the magnetic junction 100, the magnetic moment 131 can switch between stable magnetic states. Thus, in the embodiment illustrated in FIG. 2, spin transfer torque can be used to switch the magnetic moment 131 of the free layer 130. For example, the current driven in the z-axis direction can be switched so that the magnetic moment 131 is parallel or antiparallel to the magnetic moment 111 of the fixed layer 110. In certain embodiments, the free layer 130 may have a thickness of at least 1 nanometer to 10 nanometers, but is not limited thereto. For example, although illustrated with a single layer having a single magnetic moment 131, the free layer 130 may include multiple ferromagnetic and / or nonmagnetic layers. For example, the free layer 130 may be a synthetic antiferromagnetic material (hereinafter referred to as SAF) including a magnetic layer antiferromagnetically or ferromagnetically coupled through one or more thin films such as Ru. Alternatively, the free layer 130 may be a multiple layer in which one or more auxiliary layers are magnetic. Alternatively, other structures for the free layer 130 can be used.

In the illustrated embodiment, the free layer 130 can have an easy axis that follows the magnetic moment 131. The magnetic moment 131 can be stable along the easy axis. In the example shown, the magnetic moment 131 can have in-plane elements. In other words, the magnetic moment 131 can have elements that are substantially in the plane of the free layer 130. Thus, in the illustrated embodiment, the magnetic moment 131 can have elements parallel to the xy plane. In addition, the magnetic moment 131 can include elements that are substantially perpendicular to the plane. In other words, the magnetic moment 131 of the free layer 130 can have an element parallel to the z-axis of FIG. In certain embodiments, the magnetic moment 131 can be perpendicular to the plane. In such an embodiment, the in-plane element of the magnetic moment 131 may be zero. In such an embodiment, the free layer 130 may include a material such as AlMn. In such embodiments, the free layer may include a AlMn on L1 ₀ with planar and are perpendicular (100) axis. In other embodiments, the free layer 130 can include MnGa and / or MnIn.

Symmetric filter 120 may be a spin filter. Symmetric filter 120 may be a layer that transmits charge carriers having a first symmetry with a higher probability than other charge carriers having a symmetry. Transmission can take place through tunneling. In certain embodiments, the symmetric filter 120 can only transmit charge carriers having a first symmetry with a higher probability. Other symmetries can have a lower transmission probability. For example, the symmetric filter 120 may be crystalline MgO having a (100) texture. Such a layer can be transmitted to carrier current having a wave function of delta ₁ symmetric 100 direction, the higher probability carrier current having a wave function of other symmetric. Accordingly, the symmetric filter 120 can function in a manner similar to a filter that passes a carrier current having a first symmetry or does not pass a carrier current having another symmetry. In other embodiments, other materials can be used. For example, SrSnO ₃ can be used. For example, although it has been described that an insulator used as a tunneling barrier is used as the symmetric filter 120, materials having other electrical properties may be used in other embodiments.

  The pinned layer 110 may have a magnetic moment 111 fixed in a specific direction. For example, the magnetic moment 111 can be pinned through an AFM layer (not shown), a hard magnetic (not shown), or other mechanism. The pinned layer 110 shown in the figure is a single layer and is composed of a single magnetic layer. For example, although the pinned layer 110 is illustrated as a single layer having a single magnetic moment 111, the pinned layer 110 can include multiple layers. For example, the pinned layer 110 may be a SAF that includes a magnetic layer that is antiferromagnetically or ferromagnetically coupled through one or more thin films such as Ru. Alternatively, the pinned layer 110 may be another multiple layer in which one or more auxiliary layers are magnetic. Other structures for the pinned layer 110 can be used.

In the illustrated embodiment, the magnetic moment 111 can be fixed to have in-plane elements. In other words, the magnetic moment 111 can have elements that are substantially in the plane of the pinned layer 110. Thereby, the magnetic moment 111 can have an element parallel to the xy plane. In addition, the magnetic moment 111 can have elements that are substantially perpendicular to the plane. In other words, the magnetic moment 111 can have an element parallel to the z-axis of FIG. In certain embodiments, the magnetic moment 111 can be perpendicular to the plane. In such embodiments, the magnetic moment 111 can have in-plane elements that are zero. In such an embodiment, the pinned layer 110 may include a material such as AlMn. In such an embodiment, the pinned layer 110 may be composed of AlMn on L1 ₀ with 100 direction. In other embodiments, the pinned layer 110 may include MnGa.

The free layer 130 and / or the pinned layer 110 can be configured such that at least one of them has a symmetric charge carrier transmitted by a symmetric filter 120 at the Fermi level in one spin channel. . In addition, at least one of the free layer 130 and the pinned layer 110 can be depleted of charge carriers having symmetry at the Fermi level in the other spin channel. In this case, the free layer 130 and / or the fixed layer 110 can have elements of magnetizations 131 and 111 that are perpendicular to the plane. For example, the free layer 130 and / or the pinned layer 110 have charge carriers that have symmetry at the Fermi level in a number of spin channels, but charges that have symmetry at the Fermi level in a few spin channels. Can have no carrier. With ferromagnetic materials, multiple spin channels can have electrons whose spins are aligned in the total magnetization direction. A few spin channel electrons can have their spins antiparallel to the majority spin channel electrons. For a symmetrical filter 120, such as MgO with a (100) texture, that carries a carrier current with Δ ₁ symmetry, the pinned layer 110 and / or the free layer 130 are Fermi levels in multiple spin channels. It may have carrier current of delta ₁ symmetric with. However, a small number of spin channels may not have a Δ ₁ symmetric carrier current, or may have a Δ ₁ symmetric carrier current away from the Fermi level. In certain embodiments, the pinned layer 110 and / or the free layer 130 having such properties may have a magnetization that is perpendicular to the plane.

For example, the pinned layer 110 and / or the free layer 130 includes an L1 ₀ above and 100 the direction of AlMn have perpendicular magnetic moments, was found to have a predetermined symmetry at the Fermi level. More specifically, having the pinned layer 110 is perpendicular to the plane (100) axis, on L1 _0, if encompass AlMn, fixed layer 100 may have a magnetic moment 111 of the plane perpendicular. In addition, the pinned layer 110 has charge carriers having Δ ₁ symmetry at the Fermi level in a number of spin channels. Charge carriers having Δ ₁ symmetry for multiple spin channels can better carry current through the pinned layer 110. The pinned layer 110 having such a composition and structure does not have charge carriers having Δ ₁ symmetry in the (001) direction with a small number of spin channels. Such a layered band structure 160 according to an exemplary embodiment is illustrated in FIG. However, the energy bands shown are for exemplary purposes only and are not intended to accurately reflect the band structure of such materials. As shown in the band structure, a large number of spin channels can have charge carriers that are Δ ₁ symmetric at the Fermi level. The Δ ₁ symmetric charge carriers can carry current through the pinned layer 110. Free layers 130 having the same crystal structure and composition can have similar characteristics. Similarly, the pinned layer 110 and / or the free layer 130 can include MnGa and have similar properties as described above.

The pinned layer 110 and / or the free layer 130 may be used with the spin filter 120. The spin filter 120 may have a high transmission probability for charge carriers having Δ ₁ symmetry and a low transmission probability for charge carriers having other symmetric wave functions. Thus, even though all wave functions for charge carriers are expected to be attenuated by the insulating symmetric filter, the Δ ₁ wave function can be attenuated more slowly. In terms of transmission and reflection, charge carriers with Δ ₁ symmetry can be transmitted with higher probability than electrons with other symmetric wave functions. Charge carriers that are not transmitted can be reflected. For example, there is a tendency to be transmitted (100) the electron wave function having a MgO certain delta ₁ symmetric with direction, a higher probability than the electron wave function with other symmetries. FIG. 4 shows the relatively slow decay of the Δ ₁ wavefunction in MgO compared to other symmetric states. Since many spin channels have Δ ₁ symmetry at the Fermi level, many charge carriers from the Fermi level in the pinned layer 110 and the free layer 130 are transmitted through the spin filter 120. May be easy. As a result, a high level of spin polarization can be performed. Therefore, the efficiency of the spin torque induced transition can be improved and the critical current can be reduced. In this manner, the magnetic junction 100 functions in a manner similar to the conventional magnetic junction (10 in FIG. 1), but the conventional magnetic junction (10 in FIG. 1) has a Δ at the Fermi level in a number of spin channels. has _one electron, it may be used CoFe no delta ₁ electrons at the Fermi level in a small number of spin channels.

Furthermore, when using a material such as AlMn for the free layer 130 and / or the pinned layer 110, the magnetic moments 111 and 131 may be perpendicular to the plane. Thus, with the use of AlMn, the value of <H> _eff / H _k can be close to 1 or 1. This property can further reduce the critical current. As a result, the performance of the magnetic junction 100 can be improved. Thus, the magnetic junction 100 can be used in a magnetic memory, such as an STT-RAM, with improved performance. Other uses of the magnetic junction 100 may be possible.

In addition, the symmetric filter 120 may have additional characteristics with respect to the fixed layer 110 and / or the free layer 130. In certain embodiments, the lattice mismatch between the pinned layer 110 and the free layer 130 adjacent to the symmetric filter 120 may be low. As an example, the lattice mismatch between the symmetric filter 120 and the layers 110 and / or 130 can be lower than 7 percent. As another example, the lattice mismatch between the symmetric filter 120 and the layers 110 and / or 130 can be lower than 3 or 4 percent. Lattice mismatch is a difference in the lattice structure of adjacent layers. Thus, the lattice mismatch can depend on both the lattice parameters of the layer and the texture. Smaller lattice mismatches can increase the probability that the magnetic layers 110 and / or 130 have the desired magnetic anisotropy. In certain embodiments, MgO (001) can have at least 7 percent of the lattice mismatch with the AlMn of L1 _0. In certain embodiments, larger lattice mismatches can cause pinned layer 110 and / or free layer 130 with other magnetic anisotropy. Such a magnetic anisotropy induced by lattice mismatch can lead to an in-plane magnetic moment of the pinned layer 110 and / or the free layer 130. In certain embodiments, this may not be desirable. On top of that, in a given case. Lattice mismatch can adversely affect the band structure. This reduces the polarization of the carrier current, which may be undesirable. Thus, reduced lattice mismatch can be required to have the desired magnetic anisotropy and / or spin polarization. For example, the pinned layer 110 and / or the free layer 130 may have a higher perpendicular magnetic anisotropy and a plane perpendicular magnetic moment. Similarly, pinned layer 110 and / or free layer 130 may have more electrons in multiple spin channels and fewer electrons in other spin channels (or electrons in other spin channels). Can not have).

Reduced lattice mismatch can be done in a number of ways. According to certain embodiments, the grating of the symmetric filter 120 can be contracted or expanded to come close to the grating of the fixed layer 110 and / or the free layer 130. For example, the lattice parameter of MgO used for the symmetric filter 120 may be larger than the lattice parameter of the material used for the pinned layer 110 and / or the free layer 130 (eg, AlMn L1 ₀ ). Accordingly, it may be desirable for the grating of the symmetric filter 120 to be contracted. According to certain embodiments, this can be accomplished using Ge, GaAs, ZnSe for the symmetric filter 120, or other symmetric filter having a lattice parameter smaller than that of MgO. Lattice parameters of the symmetric filter 120 may be close to the lattice parameters of the AlMn L1 ₀ and / or other materials used in the fixed layer 110 and / or the free layer 130. The lattice mismatch generated between the symmetric filter 120 and the pinned layer 110 and / or the free layer 130 can be less than 7 percent. In certain embodiments, the lattice mismatch generated between the symmetric filter 120 and the pinned layer 110 and / or the free layer 130 can be less than 3 or 4 percent. Accordingly, the lattice of material used for the symmetric filter 120 can be contracted to be close to the lattice of material used for the fixed layer 110 and / or the free layer 130. In other embodiments, the lattice of the pinned layer 110 and / or the free layer 130 can be expanded. According to certain embodiments, this can be accomplished through doping or other mechanisms that can increase the lattice parameters of AlMn or other materials used in the pinned layer 110 and / or the free layer 130. In other embodiments, other materials may be used for the pinned layer 110 and / or the free layer 130. For example, MnGa and / or MnIn can be used. However, it may be desirable that the mechanism used to match the lattice closer does not unduly interfere with the magnetic properties of the pinned layer 110 and the free layer 130.

  FIG. 5 illustrates another exemplary embodiment of a magnetic memory magnetic junction 100 '. FIG. 5 may not be an actual scale. Magnetic junction 100 'may include elements similar to magnetic junction 100 illustrated in FIG. Thus, similar elements are given similar reference numbers. The magnetic junction 100 ′ includes a pinned layer 110, a symmetric filter 120, and a free layer 130, a pinned layer 110 ′, a symmetric filter 120 ′, and a free layer 130 ′, respectively. Also shown are a seed layer 102, a pinned layer 104, and a capping layer 106. According to other embodiments, seed layer 102, pinned layer 104, and capping layer 106 may be omitted. Contacts (not shown) can be provided to drive the current in the desired direction. Seed layer 102 may be used to provide a template of the desired crystal structure for pinned layer 104. The pinned layer 104 can include an AFM layer, a hard magnet, or other material used to pin the magnetization of the pinned layer 110 '.

In the illustrated embodiment, the magnetic moment 111 ′ of the pinned layer 110 ′ and the magnetic moment 131 ′ of the free layer 130 ′ can be perpendicular to the plane. Both the pinned layer 110 'and the free layer 130' each have a symmetric charge carrier that is transmitted by the symmetric filter 120 with a higher probability at the Fermi level, each within a first spin channel, such as multiple spin channels. Can be configured to have. In certain embodiments, at least one of the pinned layer 110 ′ and the free layer 130 ′ is another spin channel (eg, a small number of spin channels) and lacks Fermi level symmetric charge carriers. Can do. For example, both of the fixed layer 110 'and the free layer 130', can encompass AlMn, AlMn may have a vertical and L1 ₀ crystalline structure and surface (100) axis. Such materials have Δ ₁ electrons at the Fermi level in a large number of spin channels, but may not have Δ ₁ electrons in the (100) direction in a small number of spin channels. Furthermore, MgO or SrSnO ₃ can be used as the spin filter 120 ′, but MgO has a (100) texture. In certain embodiments, the lattice mismatch between the symmetric filter 120 ′ and the layers 110 ′ and / or 130 ′ can be lower than 7 percent. In certain embodiments, the lattice mismatch between the symmetric filter 120 ′ and the layers 110 ′ and / or 130 ′ can be lower than 3 or 4 percent. For example, the symmetric filter 120 ′ can include Ge, GaAs, and / or ZnSe. The fixed layer 110 ′ and / or the free layer 130 ′ may include MnGa and / or MnIn.

The magnetic junction 100 ′ can share the advantages of the magnetic junction 100. Since the magnetic moments 111 ′ and 131 ′ are perpendicular to the surface, the <H> _eff / H _k value can be 1. Also, the spin polarization efficiency can be improved. The performance of the magnetic junction 100 ′ can be improved.

  FIG. 6 shows another exemplary embodiment for a magnetic memory magnetic junction 100 ″. FIG. 6 may not actually be a scale. The magnetic junction 100 ″ is similar to the magnetic junction 100, 100 ′ described above. Can contain elements. Thus, similar elements bear similar reference numbers. The magnetic junction 100 "includes a pinned layer 110", a symmetric filter 120 ", and a free layer 130" similar to the pinned layers 110, 110 ', symmetric filters 120, 120', and free layers 130, 130 ', respectively. Also shown are a seed layer 102 ', a fixed layer 104', and a capping layer 106 '. According to other embodiments, the seed layer 102 ', the pinned layer 104', and the capping layer 106 'may be omitted. The seed layer 102 'can be used to provide a template of the desired crystal structure for the pinned layer 104'. The pinned layer 104 ′ may include an AFM layer, a hard magnetic material, or other material used to pin the magnetization of the pinned layer 110 ″. A contact (not shown) drives the current in the desired direction. Can be provided.

In the illustrated embodiment, the magnetic moment 131 "of the free layer 130" can be perpendicular to the plane. Also, the free layer 130 "can have symmetric charge carriers that are transmitted by the symmetric filter 120" to a higher probability at the Fermi level in a first spin channel, such as multiple spin channels. In certain embodiments, the free layer 130 "can be depleted of symmetric charge carriers at the Fermi level in other spin channels, such as a small number of spin channels. For example, the free layer 130" can contain AlMn. may include but, AlMn has L1 ₀ crystal structure, it may have a surface and a vertical (100) axis. In addition, MgO or SrSnO ₃ can be used as the spin filter 120 ″, but MgO has a (100) texture. The pinned layer 110 ″ can include other magnetic materials. For example, the pinned layer 110 "can include bcc (001) Fe, bcc (001) Co, and / or bcc (001) FeCo. In certain embodiments, the pinned layer 110" is perpendicular to the plane. Can have a magnetization (not shown). However, other directions can be possible. In certain embodiments, the lattice mismatch between the symmetric filter 120 "and the layers 110" and / or 130 "may be less than 7 percent. In certain embodiments, the symmetric filter 120" and the layers 110 ". , 130 ″ can be less than 3 or 4 percent. For example, the symmetric filter 120 "can include Ge, GaAs, and / or ZnSe. The pinned layer 110" and / or the free layer 130 "can include MnGa and / or MnIn.

Magnetic junction 100 "may share the benefits of the magnetic junction 100, 100 '. For example, the magnetic moment 131" is the plane perpendicular _may be _<H> eff / _{H k} value is 1. In addition, the spin polarization efficiency can be improved. The performance of the magnetic junction 100 "can be improved.

  FIG. 7 illustrates a magnetic junction 100 "" for a magnetic memory. FIG. 7 may not be an actual scale. The magnetic junction 100 '' 'can include elements similar to the magnetic junction 100, 100', 100 ". Accordingly, similar elements bear similar reference numbers. The magnetic junction 100 '' 'is a pinned layer. 110, 110 ′, 110 ″, symmetric filters 120, 120 ′, 120 ″, and free layers 130, 130 ′, 130 ″, fixed layers 100 ′ ″, symmetric filters 120 ′ ″, and free layers, respectively. 130 '' 'can be included. Seed layer 102 ", pinned layer 104", and capping layer 106 "are illustrated. According to other embodiments, seed layer 102", pinned layer 104 ", and capping layer 106" may be omitted. The seed layer 102 "can be used to provide a template of the desired crystal structure for the pinned layer 104". The pinned layer 104 "can include an AFM layer, a hard magnet, or other material used to pin the magnetization of the pinned layer 110" '. In addition, contacts (not shown). ) Can be provided to drive the current in the desired direction.

In the illustrated embodiment, the magnetic moment 111 ′ ″ of the pinned layer 110 ′ ″ can be perpendicular to the plane. The pinned layer 110 ′ ″ can also have symmetric charge carriers transmitted by a symmetric filter 120 ′ ″ at the Fermi level in a first spin channel, such as a number of spin channels. In certain embodiments, the pinned layer 110 '''can be depleted of charge carriers that are symmetric at the Fermi level within other spin channels, such as a small number of spin channels. For example, although the pinned layer 110 '''may include a AlMn, AlMn has L1 ₀ crystal structure, it may have a surface and a vertical (100) axis. Furthermore, MgO or SrSnO ₃ can be used as the spin filter 120 ′ ″, but MgO has a (100) texture. The free layer 130 '''can include other magnetic materials. For example, the free layer 130 '''can include bcc (001) Fe, bcc (001) Co, and / or bcc (001) FeCo. In the illustrated embodiment, the free layer 130 '''can have a magnetization that is perpendicular to the plane. However, other directions are possible. In certain embodiments, the lattice mismatch between the symmetric filter 120 ′ ″ and the layers 110 ′ ″, 130 ′ ″ can be lower than 7 percent. In certain embodiments, the lattice mismatch between the symmetric filter 120 ′ ″ and the layers 110 ′ ″, 130 ′ ″ can be lower than 3 or 4 percent. For example, the symmetric filter 120 ′ ″ can include Ge, GaAs, and / or ZnSe. The fixed layer 110 ′ ″ and / or the free layer 130 ′ ″ may include MnGa and / or MnIn.

The magnetic junction 100 ′ ″ can share the advantages of the magnetic junctions 100, 100 ′, 100 ″. Since the magnetic moment 111 ′ ″ is perpendicular to the plane, the <H> _eff / H _k value is 1. In addition, the spin polarization efficiency can be improved and the performance of the magnetic junction 100 '''can be improved.

  FIG. 8 illustrates another exemplary embodiment of a magnetic junction 200 for a magnetic memory. FIG. 8 may not be an actual scale. Magnetic junction 200 can include elements similar to magnetic junction 100, 100 '. Thus, similar elements bear similar reference numbers. The magnetic junction 100 ″ ″ includes a pinned layer 110, 110 ′, a symmetric filter 120, 120 ′, and a free layer 130, 130 ′ similar to the pinned layer 210, a symmetric filter 220, and a free layer 230, respectively. Also shown are seed layer 202, pinned layer 204, and capping layer 206, which are similar to seed layer 102, pinned layer 104, and capping layer 106, respectively. According to other embodiments, seed layer 202, pinned layer 204, and capping layer 206 may be omitted. Contacts (not shown) can be provided to drive the current in the desired direction.

In the illustrated embodiment, the pinned layer 210 and the free layer 230 may be SAF. Therefore, the pinned layer 210 includes ferromagnetic layers 212 and 216 separated by the nonmagnetic spacer layer 214. Similarly, the free layer 230 includes ferromagnetic layers 232, 236 separated by a nonmagnetic spacer layer 234. The spacer layers 214, 234 can include Ru. In the illustrated embodiment, the magnetic moments 211 and 215 of the pinned layer 210 and the magnetic moments 231 and 235 of the free layer 230 are perpendicular to the plane. In addition, the pinned layer 210 and the free layer 230 all have symmetric charge carriers, each of which is transmitted by the symmetric filter 220 at the Fermi level within one spin channel, such as multiple spin channels. Configured as follows. In certain embodiments, at least one of the pinned layer 210 and the free layer 230 can be depleted of symmetric charge carriers at the Fermi level in other spin channels, such as a few spin channels. . For example, both of the ferromagnetic layers 232 and 236 of the ferromagnetic layers 212, 216 and the free layer 230 of the pinned layer 210, can encompass AlMn, AlMn has L1 ₀ crystal structure, perpendicular to the surface Can have a (100) axis. However, in such embodiments, the spacer layers 214, 234 can allow diamagnetic coupling between the ferromagnetic layers 212, 216 and between the ferromagnetic layers 232, 236. In addition, the spacers 214, 234 can provide a growth template that is compatible with the desired crystal structure and aggregate arrangement of the ferromagnetic layers 216, 236. In addition, MgO or SrSnO ₃ can be used as the spin filter 220, but MgO has a (100) aggregate arrangement. In certain embodiments, the lattice mismatch between the symmetric filter 220 and the ferromagnetic layers 216 and / or 232 can be lower than 7 percent. In certain embodiments, the lattice mismatch between the symmetric filter 220 and the ferromagnetic layers 216 and / or 232 can be lower than 3 or 4 percent. For example, the symmetric filter 220 can include Ge, GaAs, and / or ZnSe. The ferromagnetic layers 232 and / or 216 can include MnGa and / or MnIn.

  FIG. 9 illustrates a magnetic junction 200 'for a magnetic memory. FIG. 9 may not actually be a scale. The magnetic junction 200 ′ can include elements similar to the magnetic junction 100, 100 ′, 200. Accordingly, like elements are given like reference numerals. The magnetic junction 200 ′ includes fixed layers 110, 110 ′, 210, symmetric filters 120, 120 ′, 220, and free layers 130, 130 ′, 230, similar to the fixed layers 210 ′, symmetric filters 220 ′, and free layers, respectively. Layer 230 'can be included. Also shown are a seed layer 202 ', a pinned layer 204', and a capping layer 206 '. In other embodiments, seed layer 202 ', pinned layer 204', and capping layer 206 'may be omitted. Seed layer 202 'may be used to provide a template of the desired crystal structure for pinned layer 204'. The pinned layer 204 'can include an AFM layer, a hard magnetic material, or other material used to pin the magnetization of the pinned layer 210'. A contact (not shown) can also be provided to drive the current in the desired direction.

In the illustrated embodiment, free layer 230 ′ can be a SAF that includes layers 232 ′, 234 ′, 236 ′, but layers 232 ′, 234 ′, and 236 can be similar to layers 232, 234, 236. . In the illustrated embodiment, the magnetic moments 231 ′ and 235 ′ of the free layer 230 ′ are perpendicular to the plane. In other embodiments, the magnetic moment of the pinned layer 210 ′ can be perpendicular to the plane. In addition, the free layer 230 ′ can be configured to have symmetric charge carriers transmitted by the symmetric filter 220 ′ at the Fermi level in multiple spin channels. In certain embodiments, the free layer 230 ′ can be depleted of symmetric charge carriers at the Fermi level in a few spin channels. For example, the free layer 230 'can encompass AlMn, AlMn has L1 ₀ crystal structure, it may have a surface and a vertical (100) axis. MgO or SrSnO ₃ can be used as the spin filter 220 ′, but MgO has a (100) texture.

In the illustrated embodiment, the magnetic moments 231 ′, 235 ′ of the free layer 230 ′ can be perpendicular to the plane. Moreover, the free layer 230 ′ is configured to have symmetric charge carriers that are transmitted with higher probability by a symmetric filter 220 ′ at the Fermi level within one spin channel. For example, multiple spin channels can include charge carriers that are symmetric at the Fermi level. In certain embodiments, the free layer 230 ′ may be depleted of symmetric charge carriers that are transmitted with higher probability by symmetric filters 220 ′ at the Fermi level in other spin channels, such as a small number of spin channels. it can. For example, the free layer 230 'can encompass AlMn, AlMn has L1 ₀ crystal structure, it may have a surface and a vertical (100) axis. MgO or SrSnO ₃ having a (100) aggregate arrangement can be used as the spin filter 220 ′. The pinned layer 210 ′ can include other magnetic materials. For example, the pinned layer 210 ′ can include bcc (001) Fe, bcc (001) Co, and / or bcc (001) FeCo. For example, although the magnetic moment 211 'of the pinned layer 210' is shown perpendicular to the plane, other directions are possible. In certain embodiments, the lattice mismatch between the symmetric filter 220 ′ and the layers 210 ′ and / or 232 ′ can be less than 7 percent. In certain embodiments, the lattice mismatch between the symmetric filter 220 'and the layers 210', 232 'can be lower than 3 or 4 percent. For example, the spin filter 220 ′ can include Ge, GaAs, and / or ZnSe. Layers 232 ′ and / or 210 ′ can include MnGa and / or MnIn.

  Fig. 10 illustrates a magnetic junction 200 "for a magnetic memory. Fig. 10 may not be an actual scale. The magnetic junction 200" includes elements similar to the magnetic junction 100, 100 ', 200, 200'. be able to. Accordingly, like elements are given like reference numerals. The magnetic junction 200 ″ is a pinned layer 210 similar to the pinned layers 110, 110 ′, 210, 210 ′, the symmetric filters 120, 120 ′, 220, 210 ′, and the free layers 130, 130 ′, 230, 230 ′. ", Including a symmetric filter 220" and a free layer 230 ". Also shown are seed layer 202 ", pinned layer 204", and capping layer 206 ". According to other embodiments, seed layer 202", pinned layer 206 ", and capping layer 206" may be omitted. The seed layer 202 "can be used to provide a template of the desired crystal structure for the pinned layer 204". The pinned layer 204 "can include an AFM layer, a hard magnetic material, or other material used to pin the magnetization of the pinned layer 210". A contact (not shown) can also be provided to drive the current in the desired direction.

In the illustrated embodiment, the pinned layer 210 ″ may include layers 212 ′, 214 ′, 216 ′, although layers 212 ′, 214 ′, and 216 may be similar to layers 212, 214, 216. The magnetic moment 211 ", 215" of the pinned layer 210 "is perpendicular to the plane. In other embodiments, the magnetic moment of the free layer 230 "can be perpendicular to the plane. In addition, the free layer 210" can be a symmetrical filter 220 at the Fermi level in one spin channel, such as multiple spin channels. Can be configured to have symmetrical charge carriers that are transmitted with a higher probability. In certain embodiments, the pinned layer 210 "is Fermi quasi in other spin channels, such as a small number of spin channels. Symmetric charge carriers at the position can be depleted. For example, although the pinned layer 210 'may include a AlMn, AlMn has L1 ₀ crystal structure, a surface perpendicular (100) .MgO or SrSnO ₃ spin filter 220 shaft may have a "MgO has a (100) texture.

In the illustrated embodiment, the magnetic moments 211 ", 215" of the pinned layer 210 "are perpendicular to the plane. In addition, the pinned layer 210" is Fermi within one spin channel, such as multiple spin channels. It is configured to have symmetric charge carriers that are transmitted with higher probability by a symmetric filter 220 "at the level. In certain embodiments, the pinned layer 210" has other spin channels such as a small number of spin channels. Symmetric charge carriers at the Fermi level can be depleted in the channel. For example, although the pinned layer 210 'may include a AlMn, AlMn has L1 ₀ crystal structure, a surface perpendicular (100) .MgO or SrSnO ₃ spin filter 220 shaft may have a "MgO has a (100) texture. The free layer 230 "can include other magnetic materials. For example, the free layer 230" can include bcc (001) Fe, bcc (001) Co, and / or bcc (001) FeCo. Even though the magnetic moment 231 ″ of the free layer 230 ″ is shown perpendicular to the plane, other directions are possible. In certain embodiments, the lattice mismatch between the symmetric filter 220 "and the layers 216 ', 230" can be lower than 7 percent. In certain embodiments, the lattice mismatch between the symmetric filter 220 "and the layers 216 ', 230" can be lower than 3 or 4 percent. For example, the symmetric filter 220 "can include Ge, GaAs, and / or ZnSe. Layers 232" and / or 216 "can include MnGa and / or MnIn.

The magnetic junctions 200 ″, 200, 200 ′ can share the advantages of the magnetic junctions 100, 100 ′, 100 ″. For example, the magnetic moments of the layers 210 ″ and 230 ″, 210, 210 ′, 230, 230 ′ may be perpendicular to the plane and the <H> _eff / H _k value may be unity. In addition, the spin polarization efficiency can be improved. The performance of the magnetic junctions 200 ″, 200, 200 ′ can be improved.

  FIG. 11 illustrates a magnetic junction 300 for a magnetic memory. FIG. 11 may not be an actual scale. The magnetic junction 300 can include elements similar to the magnetic junctions 100, 100 ', 100 ", 100"', 200, 200 ', 200 "described in the examples of FIGS. Accordingly, like elements are given like reference numerals. The magnetic junction 300 includes a pinned layer 310, a symmetric filter 320, and a free layer 330, which are similar to the pinned layers 110, 110 ′, 210, the symmetric filters 120, 120 ′, 220, and the free layers 130, 130 ′, 230, respectively. Can be included. The seed layers 102, 102 ′, 102 ″, 202, 202 ′, 202 ″, the fixed layers 104, 104 ′, 104 ″, 204, 204 ′, 204 ″, 204 ′ ″, and the capping layers 106, 106 ′. , 106 ″, 206, 206 ′, 206 ″, respectively, a seed layer 302, a fixed layer 304, and a capping layer 306 are illustrated. According to other embodiments, the seed layer 302, the pinned layer 304, and the capping layer 306 may be omitted. The magnetic junction 300 can include an additional spacer layer 340, an additional pinned layer 350, and an additional pinned layer 360. Accordingly, the magnetic junction 300 is similar to the magnetic elements 100, 100 ′, 100 ″, 100 ′ ″, 200, 200 ′, 200 ″ described above in addition to the additional layers 340, 350, 360. Can be included.

In the illustrated embodiment, the additional spacer layer 340 can be a tunnel barrier layer. In other embodiments, the additional spacer layer 340 can be conductive. Further, in other embodiments, the additional spacer layer 340 can be a symmetric filter such as MgO described above. The additional pinned layer 350 may be similar to the pinned layers 110, 110 ′, 110 ″, 110 ′ ″, 210, 210 ′, 210 ″ described above. Thus, the additional pinned layer 350 can have symmetric charge carriers that are transmitted with higher probability by the symmetric filter 320 at the Fermi level within one spin channel, such as multiple spin channels. In certain embodiments, the additional pinned layer 350 can be depleted of symmetric charge carriers at the Fermi level in other spin channels, such as a few spin channels. For example, although additional fixation layer 350 may include a AlMn, AlMn has L1 ₀ crystal structure, it may have a surface and a vertical (100) axis. Therefore, the magnetic moment 351 of the additional pinned layer 350 can be perpendicular to the plane. Note that although magnetic moments 311 and 315 are illustrated anti-parallel, other configurations can be used. In addition, SrSnO ₃ or MgO with a (100) texture can be used and the spacer layer 340 can serve as a spin filter. Even though a single layer is illustrated, one or more of layers 310, 350, and 360 may be SAF. In certain embodiments, the lattice mismatch between the symmetric filter 320 and the layers 310 and / or 330 can be less than 7 percent. In certain embodiments, the lattice mismatch between the symmetric filter 320 and the layers 310 and / or 330 can be lower than 3 or 4 percent. For example, the symmetric filter 320 can include Ge, GaAs, and / or ZnSe. Layers 310 and / or 320 can include MnGa and / or MnIn. Similarly, if the additional spacer layer 340 is a symmetric filter, the lattice mismatch between the additional spacer layer 340 and layers 330 and / or 360 can be lower than 7 percent. For example, the lattice mismatch between the additional spacer layer 340 and the layers 330 and / or 360 can be lower than 3 or 4 percent. Layers 330 and / or 360 can include MnGa and / or MnIn.

The double magnetic junction 300 can share the benefits of the magnetic junctions 100, 100 ′, 100 ″, 200, 200 ′, 200 ″. For example, the magnetic moments of layers 210, 210 ′, 210 ″, 310, 230, 230 ′, 230 ″, 330, and optionally 350, are perpendicular to the plane, and the <H> _eff / H _k value is 1. . In addition, the spin polarization efficiency can be improved. The performance of the magnetic junction 300 can be improved.

  FIG. 12 illustrates an exemplary embodiment of a magnetic memory 400 using a double magnetic junction. In the illustrated embodiment, the magnetic memory 400 is an STT-RAM. The magnetic memory 400 includes not only the word line selector / driver 404 but also read / write column selector / drivers 402 and 406. The magnetic memory 400 includes a memory cell 410 including a magnetic junction 412 and a selection / separation element 414. The magnetic junction 412 can be any one of the magnetic junctions 100, 100 ', 100 ", 100" ", 200, 200', 200", 300 described above. Read / write column selector / drivers 402, 406 can be used to selectively drive current through bit line 403 and cell 410. The selection / separation element 414 can be coupled to the selected word line 405 so that the word line selector / driver 404 can select a column of the magnetic memory 400.

  Since the magnetic memory 400 can use the magnetic junctions 100, 100 ′, 100 ″, 200, 200 ′, 200 ″, and 300 described above, the magnetic memory 400 has the magnetic junctions 100, 100 ′, 100 ″, 200. , 200 ′, 200 ″, 300 can be shared. Therefore, the performance of the magnetic memory 400 can be improved.

  FIG. 13 illustrates a method 500 for manufacturing a double magnetic tunneling junction for a magnetic memory. Method 500 may be described in terms of magnetic junction 100, 110 '. However, the method 500 can also be used in the manufacture of other magnetic junctions. In addition, some steps may be omitted for ease of explanation. Method 500 may be combined with additional and / or other processes. The method of manufacturing 500 is also described in terms of manufacturing a single magnetic junction. However, the method 500 can form multiple magnetic junctions 300, as in the example for magnetic memory, for example.

  A magnetic junction stack is provided (step 502). The magnetic junction stack includes a fixed layer film, a spin filter film, and a free layer film. In addition, if the magnetic junction 300 described as an example in FIG. 11 is manufactured, the magnetic junction stack can include a spacer film and an additional fixed layer film. In certain embodiments, the magnetic junction stack can be annealed at step 502.

  Magnetic junctions 100, 100 ', 100 ", 100" ", 200, 200', 200", 300 may be defined from the magnetic junction stack (stage 504). Step 504 can include providing a mask over a portion of the magnetic junction stack and then removing a portion of the exposed magnetic junction stack. The magnetic junctions 100, 100 ′, 100 ″, 100 ′ ″, 200, 200 ′, 200 ″, 300 are fixed layers 110, 110 ′, 110 ″, 110 ′ ″ defined from the first fixed layer film, 210, 210 ′, 210 ″, 310, symmetric filters 120, 120 ′, 120 ″, 220, 220 ′, 220 ″, 320 defined from spin filter films, and free layers 130, 130 defined from free layer films. ', 130 ", 130'", 230, 230 ', 230 ", 330 can be included. In certain embodiments, the magnetic junction 300 can include an additional spacer 340 and an additional pinned layer 350.

  The magnetization directions of the pinned layers 110, 110 ', 110 ", 110" ", 210, 210', 210", 310 may be set (step 506). For example, step 506 applies a magnetic field in the desired direction while the magnetic junctions 100, 100 ′, 100 ″, 100 ′ ″, 200, 200 ′, 200 ″, 300 are heated, and in the presence of the magnetic field. The magnetic junctions 100, 100 ′, 100 ″, 100 ′ ″, 200, 200 ′, 200 ″, 300 can be cooled to proceed.

  Thereby, the magnetic junctions 100, 100 ', 100 ", 100" ", 200, 200', 200", 300 can be manufactured. The magnetic junction and / or magnetic memory fabricated through the method 500 can share the advantages of the magnetic junction 100, 100 ′, 100 ″, 100 ′ ″, 200, 200 ′, 200 ″ and / or the magnetic memory 400. . As a result, the performance of the magnetic junction 100, 100 ', 100 ", 100"', 200, 200 ', 200 "and / or the magnetic memory 400 may be improved.

  Thus, a manufacturing method and system related to a magnetic junction and a memory manufactured using the magnetic memory junction are disclosed. The method and system are disclosed by the embodiments, and those skilled in the art can easily understand that various modifications can be made to the embodiments. Accordingly, various modifications may be made by those skilled in the art within the scope of the claims and the invention appended hereto.

102, 202, 302 Seed layer 104, 204, 304 Fixed layer 106, 206, 306 Capping layer 110, 210, 310 Fixed layer 111, 131, 211, 215, 231, 235 Magnetic moment 120, 220, 320 Symmetric filter 130 , 230, 330 Free layer 212, 216, 232, 236 Ferromagnetic layer 214, 234, 340 Spacer layer 100, 200, 300 Magnetic junction 400 Magnetic memory 402, 406 Read / write column selector / driver 403 Bit line 404 Word line selector / Driver 412 magnetic junction 414 selection / separation element

Claims (27)

A free layer having a first magnetic moment that is switchable between a plurality of stable magnetic states when a write current passes through the magnetic junction;
A symmetric filter for transmitting charge carriers having a first symmetry with a higher probability than charge carriers having a second symmetry;
A pinned layer having a second magnetic moment fixed in one direction,
The symmetrical filter is interposed between the free layer and the pinned layer;
At least one of the pinned layer and the free layer has the first symmetric charge carrier at a Fermi level in one spin channel and the first symmetry at a Fermi level in another spin channel. Having a non-zero magnetic moment element that is depleted of, is disposed in-plane and is perpendicular to the plane,
A magnetic junction having a lattice mismatch of less than 7 percent between the symmetric filter and at least one of the pinned layer and the free layer.   The magnetic junction of claim 1 wherein the lattice mismatch is lower than 4 percent.   The magnetic junction according to claim 1, wherein at least one of the free layer and the pinned layer includes AlMn.   The magnetic junction of claim 1, wherein the symmetric filter comprises at least one of Ge, GaAs, and ZnSe.   The magnetic junction of claim 1, wherein the first magnetic moment is perpendicular to the plane.   The magnetic junction of claim 1, wherein the second magnetic moment is perpendicular to the plane.   The magnetic junction of claim 1, wherein at least one of the free layer and the pinned layer comprises at least one of MnGa and MnIn.   The magnetic junction of claim 1, wherein the symmetric filter is a tunnel barrier layer.   The magnetic junction according to claim 1, wherein at least one of the free layer and the pinned layer is a synthetic diamagnetic material. A spacer layer;
An additional pinned layer,
The spacer layer is interposed between the free layer and the additional pinned layer;
The magnetic junction of claim 1, wherein the additional pinned layer has a third magnetic moment.   The magnetic junction of claim 10, wherein the additional pinned layer comprises AlMn.   The magnetic junction of claim 10, wherein the spacer layer is an additional symmetric filter.   The magnetic junction of claim 11 having an additional lattice mismatch of less than 7 percent between the additional symmetric filter and at least one of the free layer and the additional pinned layer. .   The magnetic junction of claim 13, wherein the additional lattice mismatch is lower than 4 percent.   The magnetic junction of claim 12, wherein the additional symmetric filter comprises at least one of Ge, GaAs, and ZnSe.   The magnetic junction according to claim 10, wherein the free layer, the pinned layer, and the additional pinned layer are synthetic antiferromagnetic materials. Includes AlMn having a (001) axis parallel to the plane and perpendicular to the plane, and has a first magnetic moment that is switched between a number of stable magnetic states when the write current passes through the magnetic junction. And having a first symmetric charge carrier at the Fermi level in the first plurality of spin channels, the first symmetric charge carrier being depleted in the first few spin channels, and the first magnetic moment Is a free layer having a first non-zero element perpendicular to the plane;
A symmetric filter that transmits the charge carrier having the first symmetry, attenuates the charge carrier having a second symmetry different from the first symmetry, and includes at least one of Ge, GaAs, and ZnSe;
A second magnetic moment that is parallel to the surface and includes a second non-zero element that is perpendicular to the surface, the AlMn having a (001) axis that is perpendicular to the surface, and is fixed in one direction. And having a first symmetric charge carrier at the Fermi level in a second plurality of spin channels and depleting the first symmetric charge carrier in a second few spin channels A layer, and
A magnetic junction for a magnetic memory element, wherein the symmetric filter is interposed between the free layer and the fixed layer. At least one selection element and at least one magnetic junction, the at least one magnetic junction comprising a free layer, a pinned layer, and a symmetrical filter interposed between the free layer and the pinned layer; The free layer has a first magnetic moment that switches between a plurality of stable magnetic states when a write current passes through the magnetic junction, and the symmetric filter includes charge carriers having a first symmetry; Transmitting with higher probability than the charge carriers having two symmetry, the pinned layer has a second magnetic moment pinned in one direction, and at least one of the free layer and the pinned layer is The first symmetric charge at the Fermi level in the second spin channel with the first symmetric charge carrier at the Fermi level in one spin channel The carrier is depleted, has a non-zero magnetic moment element disposed in-plane and perpendicular to the plane, and the symmetric filter and at least one of the free layer and the pinned layer is greater than 7 percent A plurality of magnetic storage cells having low lattice mismatch;
A plurality of bit lines coupled to the plurality of magnetic storage cells;
And a plurality of word lines coupled to the plurality of magnetic storage cells.   The magnetic memory of claim 18, wherein the lattice mismatch is less than 4 percent.   The magnetic memory of claim 18, wherein the symmetric filter comprises at least one of Ge, GaAs, and ZnSe. A first non-zero element that is parallel to a plane and has a first magnetic moment that switches between a plurality of stable magnetic states when a read current passes through, the first magnetic moment being perpendicular to the plane; Having a free layer;
A pinned layer having a second magnetic moment parallel to the surface and fixed in one direction;
A symmetric filter interposed between the free layer and the pinned layer,
The second magnetic moment has a second non-zero element perpendicular to the plane;
At least one of the free layer and the pinned layer has a first symmetric charge carrier at Fermi energy within a first majority of spin channels, and the first symmetry with a first few spin channels. Are depleted of charge carriers,
The symmetrical filter transmits the charge carrier having the first symmetry and attenuates the charge carrier having a second symmetry different from the first symmetry;
The magnetic junction for a magnetic memory element, wherein the symmetric filter and at least one of the free layer and the pinned layer have a lattice mismatch of less than 7 percent. Parallel to the plane and having a first magnetic moment that switches between a plurality of stable magnetic states when the read current passes through, and a first symmetry at the Fermi level in the first plurality of spin channels. A free layer having charge carriers, depleted of the first symmetric charge carriers in a first minority spin channel, and wherein the first magnetic moment has a first non-zero element perpendicular to the plane;
A symmetric filter for transmitting charge carriers having the first symmetry and attenuating charge carriers having a second symmetry different from the first symmetry;
Having a second magnetic moment parallel to the plane and fixed in one direction, having the first symmetric charge carrier at the Fermi level in a second plurality of spin channels, and a second minority A pinned layer having a second non-zero element that is depleted of the first symmetric charge carriers in the spin channel and wherein the second magnetic moment is perpendicular to the plane;
The symmetrical filter is interposed between the fixed layer and the free layer;
A magnetic junction for a magnetic memory element, wherein the symmetric filter and at least one of the free layer and the pinned layer have a lattice mismatch of less than 7 percent. A magnetic junction stack including a free layer film, a pinned layer film, and a symmetric filter film is provided, wherein the symmetric filter film transmits charge carriers having a first symmetry and attenuates the charge carriers having a second symmetry. The first symmetric charge at a Fermi level in one spin channel, wherein at least one of the fixed layer film and the free layer film is interposed between the free layer film and the fixed layer film. A non-zero magnetic moment element having carriers, wherein the first symmetric charge carriers at the Fermi level in the other spin channel are depleted, placed in-plane and perpendicular to the plane, and the symmetric filter A film and at least one of the free layer film and the pinned layer film have a lattice mismatch of less than 7 percent;
A free layer defined from the free layer film, a symmetric filter defined from the symmetric filter film, a pinned layer defined from the pinned layer film, the free layer having a first magnetic moment, Defining a magnetic junction in which the pinned layer has a second magnetic moment;
Setting the second magnetic moment of the pinned layer fixed in a specific direction,
A method of manufacturing a magnetic junction for a magnetic memory element, wherein the magnetic junction is configured such that the first magnetic moment switches between a plurality of stable magnetic states when a read current passes through the magnetic junction.   24. The method of manufacturing a magnetic junction for a magnetic memory element according to claim 23, wherein the lattice mismatch is lower than 4 percent.   24. The magnetic junction for a magnetic memory element according to claim 23, wherein at least one of the free layer film and the fixed layer film includes AlMn disposed in a plane and having a (001) axis perpendicular to the plane. Manufacturing method.   24. The method of manufacturing a magnetic junction for a magnetic memory element according to claim 23, wherein the symmetric filter includes at least one of Ge, GaAs, and ZnSe. Providing the magnetic junction stack;
Forming a spacer layer film;
Forming an additional pinned film for the additional pinned layer,
The spacer layer is interposed between the additional fixed layer film and the free layer film;
24. The method of manufacturing a magnetic junction for a magnetic memory element according to claim 23, wherein the additional pinned layer has a third magnetic moment.