CN110299446B - Electric control magneton valve structure based on acoustic wave excitation - Google Patents
Electric control magneton valve structure based on acoustic wave excitation Download PDFInfo
- Publication number
- CN110299446B CN110299446B CN201910550803.7A CN201910550803A CN110299446B CN 110299446 B CN110299446 B CN 110299446B CN 201910550803 A CN201910550803 A CN 201910550803A CN 110299446 B CN110299446 B CN 110299446B
- Authority
- CN
- China
- Prior art keywords
- substructure
- magnetic
- layer
- valve
- acoustic wave
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N50/00—Galvanomagnetic devices
- H10N50/10—Magnetoresistive devices
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N52/00—Hall-effect devices
- H10N52/101—Semiconductor Hall-effect devices
Landscapes
- Hall/Mr Elements (AREA)
Abstract
The invention belongs to the field of memories, and discloses an electric control magneton valve structure based on acoustic wave excitation, which comprises a thin film acoustic wave resonator substructure, a magneton valve substructure and a ferroelectric exchange bias heterojunction substructure, wherein the thin film acoustic wave resonator substructure, the magneton valve substructure and the ferroelectric exchange bias heterojunction substructure are positioned on a substrate (1) from top to bottom; the thin film acoustic wave resonator substructure is used for providing acoustic wave excitation to the magnetic sub-valve substructure; the resonance frequency and amplitude of the generated acoustic wave are regulated and controlled by utilizing the film acoustic wave resonator substructure, and ferromagnetic resonance is realized to excite the size of a magnetic current in the magnetic sub-valve substructure, so that the conduction and the cut-off of the magnetic sub-valve substructure are realized, and the excitation of the magnetic sub-valve effect of the magnetic sub-valve substructure is realized. According to the invention, through improving other substructures and the like which are correspondingly matched and arranged in a key excitation mode of the magnetic sub-valve, the structure can realize ferromagnetic resonance by adjusting resonance frequency and amplitude through the FBAR so as to excite the magnetic sub-flow in the magnetic sub-valve, realize the on-off of a device and achieve the storage function.
Description
Technical Field
The invention belongs to the field of memories, and particularly relates to an electric control magneton valve structure based on acoustic wave excitation.
Background
Since half a century, the transistor technology for regulating semiconductor conductivity by electric field has been rapidly developed, and the moore's law proposed in 1965 is verified. At present, the CMOS integration process has been developed to be below 5nm, the basic mode of the transistor technology is not changed, only the development from the physical scale is realized, and the Moore's law is difficult to continue. To meet the requirements of the development of high-speed and low-power computing and memory technologies in the post-molar age, a great deal of effort has been made to find new technologies, including microelectronic technologies based on electron spin, electron tunnel, ferroelectric, strain and phase change, to develop the next generation of microelectronic Devices with smaller cell size, non-volatility, low power consumption and high speed [ dmitrii e.nikonov, Ian a.young.benchmark of Beyond-CMOS expression Devices for Logic Integrated circuits.ieee Journal on expression Devices and circuits.16july2015 ].
To further solve the increasingly outstanding high device power consumption and heat generation problems of spintronic devices due to size reduction, attention has been directed to spintronic devices [ Zhang Steven s. -L, Zhang shufeng, magnon medical Electric Current source vacuum a Ferromagnetic Insulator layer.10.1103/physrevlet.109.096603.2012 ], and a magnetovalve structure of magnetic Insulator/nonmagnetic metal/magnetic Insulator (MI/NM/MI) was proposed in 2018. The spin valve is characterized in that a spin valve structure similar to a structure utilizing a giant magneto-resistance effect (GMR) and a tunneling magneto-resistance effect (TMR) is adopted, electron transmission is avoided, and the size of magnetic current is regulated and controlled by changing the orientation of the relative magnetization directions of two magnetic insulation layers. Spin valves based on GMR and TMR effects reflect the switching state by the resistance value, whereas spin wave based magnetovalves are mainly detected by the inverse spin hall effect. The spin-wave-based spin-like valve is named as a magneton valve, and researchers observe the spin-wave effect by using a magnetic nonmetal as a magnetic pole material and an insulating barrier layer to avoid interference of electron behaviors. The magneton valve can avoid joule heat generated by electron transmission, and has the potential of reducing power consumption. The Moscow institute of Physics and technology, Sergei Nikitov et al, indicates that 99% of the energy consumed by present day memory systems is wasted in "heat dissipation" [ A.Klimov, N.Tiercein, Y.Dusch, S.Giordano, T.Mathurin, P.Pernod, V.Preobazzenky, A.Churbanov, S.Nikitov.Magnetoelectric write and read operations in a stress-mediated multiple semiconductor memory cells 110(22):222401. y 2017 ]. Meanwhile, the spin wave has two characteristics of amplitude and phase, is expected to break through the logic and calculation architecture of the traditional von Neumann system, and becomes one of the important modes of information transmission and processing in the post-molar era.
The Chinese invention patent CN 107293641A proposes that the coupling effect of the ferroelectric and ferromagnetic interface is strengthened by preparing the heterojunction of the Co nanodots and the BiFeO3 thin film, and the controllability of the electromagnetic writing and reading is improved by taking strain as the regulation and control mechanism of the electromagnetic writing and reading. But it only does the control of the magnetic moment by the electric field and does not realize the reversible control of the overall magnetism observed by the macroscopic hysteresis loop.
Chinese invention patent CN 104362250B proposes an electroresistance-variable heterojunction with exchange bias effect, which only realizes an electrically controlled exchange bias heterojunction structure, and does not form an original device (the device cannot be well formed only by the exchange bias effect, and the performance of the device is achieved, so the prior art does not study on exchange bias but does not further study on the original device), and thus the whole regulation and control performance of the electric field on the device effect cannot be reflected. And the change of resistance state caused only based on the exchange bias effect is limited, and the information is easy to lose when the method is applied to storage.
So far, most of multiferroic heterostructures can only realize the regulation and control of the magnetic moment by an electric field, the regulation and control of the magnetic moment direction mostly need the assistance of a magnetic field, most of electric control is volatile, and the technology for realizing the magnetic moment rotation and magnetic resistance change in an electric field nonvolatile regulation and control spintronics device under the assistance of no magnetic field is not provided. The chinese invention patent CN 109103329a proposes an electrically controlled spin valve structure and a nonvolatile memory device. The magnetic field regulation device realizes the change of magnetic moment rotation and magnetic resistance in the electric field regulation device based on the spin valve structure, realizes the electric control magnetic storage function, can still realize electric writing if the spin valve is replaced by the magnetic sub-valve, and can further reduce the power consumption of the device. As a novel magnetic sub-valve device, the breakthrough of the magnetic sub-valve device in materials, physics and devices can become a novel computer column core device with low energy consumption, rewritability, nonvolatility and high frequency.
At present, a magneton spinning device has just been created, and a magneton Valve structure has also just been proposed [ Wu H, Huang L, Fan C, et al. The currently proposed magneton valve device is based on a temperature gradient excitation mode, is easily influenced by the ambient temperature, and is applied to a large-scale integrated circuit, so that the development of a spin wave excitation, regulation and detection means matched with a magneton valve structure and the development of a corresponding magneton spin prototype device are urgently needed.
Disclosure of Invention
In view of the above defects or improvement needs in the prior art, an object of the present invention is to provide an electric control magneton valve structure based on acoustic wave excitation, in which other substructures (e.g., a thin film acoustic wave resonator substructure, a ferroelectric exchange bias heterojunction substructure) and the like that are correspondingly and cooperatively arranged are improved by a key excitation manner of the magneton valve, so that the structure can realize ferromagnetic resonance by adjusting resonance frequency and amplitude through FBAR to excite the magnitude of a magneton current in the magneton valve, thereby realizing the switching on and off of a device and achieving a storage function. The electric control magneton valve structure based on the acoustic wave excitation is particularly suitable for being applied under the room temperature condition, and different from the prior art that the function of the electric control magneton valve is realized by using the gradient temperature. In addition, due to the adoption of a mode of acoustic wave excitation, the device has the excellent characteristics of smaller size, easy integration, high frequency and low power consumption.
To achieve the above object, according to one aspect of the present invention, there is provided an electrically controlled magneton-valve structure based on bulk acoustic wave excitation, comprising, from top to bottom, a thin film bulk acoustic wave resonator substructure, a magneton-valve substructure and a ferroelectric exchange bias heterojunction substructure on a substrate (1), wherein,
the thin film acoustic bulk wave resonator substructure is used for providing acoustic bulk wave excitation for the magnetic sub-valve substructure, and comprises a piezoelectric film (7) and electrode layers (8) which are positioned at two ends of the piezoelectric film (7) and used for applying voltage to the piezoelectric film (7), and the thin film acoustic bulk wave resonator substructure can generate acoustic bulk waves under the action of the applied voltage and can regulate and control the resonant frequency and amplitude of the acoustic bulk waves through different applied voltages;
the magnetic sub-valve structure is a magnetic sub-valve structure of a magnetic insulator/non-magnetic metal/magnetic insulator and comprises a first magnetic insulating layer (4), a non-magnetic metal layer (5) and a second magnetic insulating layer (6) which are distributed from bottom to top;
the resonance frequency and the amplitude of the generated acoustic wave are regulated and controlled by utilizing the film acoustic wave resonator substructure, and ferromagnetic resonance is realized to excite the size of magnetic sub-flow in the magnetic sub-valve substructure, so that the conduction and the cut-off of the magnetic sub-valve substructure are realized, and the excitation of different magnetic sub-flow sizes of the magnetic sub-valve substructure is realized;
the ferroelectric exchange bias heterojunction substructure and the magneton valve substructure share the second magnetic insulating layer (6), the ferroelectric exchange bias heterojunction substructure further comprises a multiferroic layer (3) and a bottom electrode (2) positioned below the multiferroic layer (3), the multiferroic layer (3) and the second magnetic insulating layer (6) form a heterojunction, the ferroelectric exchange bias heterojunction substructure achieves the effect of regulating and controlling the magnetic moment of the second magnetic insulating layer (6) through the exchange bias effect of the heterojunction, and the relative orientation of the magnetic moments of the first magnetic insulating layer (4) and the second magnetic insulating layer (6) is matched and regulated to realize the conduction and the cut-off of the magneton valve.
According to another aspect of the present invention, there is provided an electrically controlled magneton-valve structure based on bulk acoustic wave excitation, comprising, from top to bottom, on a substrate (1), a thin film bulk acoustic wave resonator substructure, a magneton-valve substructure and a ferroelectric exchange-biased heterojunction substructure, wherein,
the thin film acoustic bulk wave resonator substructure is used for providing acoustic bulk wave excitation for the magnetic sub-valve substructure, and comprises a piezoelectric film (7) and electrode layers (8) which are positioned at two ends of the piezoelectric film (7) and used for applying voltage to the piezoelectric film (7), and the thin film acoustic bulk wave resonator substructure can generate acoustic bulk waves under the action of the applied voltage and can regulate and control the resonant frequency and amplitude of the acoustic bulk waves through different applied voltages;
the magnetic sub-valve structure is a magnetic sub-valve structure of a magnetic insulator/nonmagnetic metal/magnetic insulator and comprises a first magnetic insulating layer (4), an antiferromagnetic insulating layer and a second magnetic insulating layer (6) which are distributed from bottom to top;
the resonance frequency and the amplitude of the generated acoustic wave are regulated and controlled by utilizing the film acoustic wave resonator substructure, and ferromagnetic resonance is realized to excite the size of magnetic sub-flow in the magnetic sub-valve substructure, so that the conduction and the cut-off of the magnetic sub-valve substructure are realized, and the excitation of different magnetic sub-flow sizes of the magnetic sub-valve substructure is realized;
the ferroelectric exchange bias heterojunction substructure and the magneton valve substructure share the second magnetic insulating layer (6), the ferroelectric exchange bias heterojunction substructure further comprises a multiferroic layer (3) and a bottom electrode (2) positioned below the multiferroic layer (3), the multiferroic layer (3) and the second magnetic insulating layer (6) form a heterojunction, the ferroelectric exchange bias heterojunction substructure achieves the effect of regulating and controlling the magnetic moment of the second magnetic insulating layer (6) through the exchange bias effect of the heterojunction, and the relative orientation of the magnetic moments of the first magnetic insulating layer (4) and the second magnetic insulating layer (6) is matched and regulated to realize the conduction and the cut-off of the magneton valve.
As a further preferred aspect of the present invention, in the ferroelectric exchange bias heterojunction substructure, the multiferroic layer (3) is specifically BiFeO3A multiferroic layer, preferably a layer of Ti or Nb doped BiFeO3Layer and a layer of rare earth element doped BiFeO3And (3) a layer.
As a further preferred aspect of the present invention, in the ferroelectric exchange bias heterojunction substructure, the lattice mismatch ratio between the multiferroic layer (3) and the bottom electrode (2) is less than 10%.
As a further preferred aspect of the present invention, the bottom electrode (2) is SrRuO3。
In a further preferred embodiment of the present invention, in the thin film acoustic wave resonator substructure, the piezoelectric thin film (7) is an AIN piezoelectric thin film;
the electrode layers (8) are an upper layer and a lower layer and are respectively positioned on the upper surface and the lower surface of the piezoelectric film (7); the thin film bulk acoustic wave resonator substructure is capable of generating bulk acoustic waves with a propagation direction perpendicular to the piezoelectric thin film (7).
In a further preferred embodiment of the present invention, in the magneton-valve substructure, the first magnetic insulating layer (4) and the second magnetic insulating layer (6) are both Y3Fe5O12A layer;
the nonmagnetic metal layer (5) is a metal single layer or a metal oxide layer containing nonmagnetic metal, and is specifically Au, Pt or MgO.
In a further preferred embodiment of the present invention, the first magnetic insulating layer (4) and the second magnetic insulating layer (6) are both Y3Fe5O12A layer;
the antiferromagnetic insulating layer is NiO.
As a further preferred aspect of the present invention, the substrate (1) is a ferroelectric single crystal, preferably SrTiO3And (3) single crystal.
Compared with the prior art, the technical scheme of the invention has the advantages that on one hand, the following steps are performed in principle: because the spin wave is a collective excited state of a spin precession process in a magnetic system, quantized quasi-particles of the spin wave are called magnetons, and each magneton carries a spin angular momentum of a Planck constant; compared to spin-polarized conduction electrons in conventional metals, the spin-wave based magnetons have the following advantages: 1. the transmission of the magnetons has the characteristics of no heat dissipation and low damping, and has remarkable advantages in long-distance spin information transmission; 2. the fluctuation property of the magnetons has two characteristics of amplitude and phase, the logic and calculation architecture of the traditional von Neumann system can be broken through, and the magneton magneto. In another aspect, in an implementation: the invention adopts FBAR structure-based acoustic wave excitation to generate spin wave to realize magneton valve effect, the electric control excitation mode is effective and is not influenced by the environmental temperature, and the magneton transistor (magneton valve) based on pure spin current is faster and more efficient than the traditional electronic device and circuit. The invention obtains the electric control magnetic sub-valve structure excited by the acoustic wave based on the novel magnetic sub-valve structure, the electric control multi-ferromagnetic heterojunction structure and the film acoustic wave resonator structure, and the electric control magnetic sub-valve structure can not be influenced by temperature within a normal temperature range (such as the temperature condition of 20-40 ℃) (because the generation of the acoustic wave is not easily influenced by the ambient temperature, the integral operation of the device can not be influenced basically under the condition that the excitation is not easily influenced by the environment), and the electric control magnetic sub-valve structure can be applied at room temperature especially. The structure is applied to a magnetic sub-valve effect structure based on MI/NM/MI (or MI/AFI/MI) for the first time, a sandwich structure based on sound wave excitation, namely a film sound wave resonator (FBAR), is arranged on the magnetic sub-valve structure, the resonant frequency and amplitude are adjusted through the sandwich structure, and a ferromagnetic resonance effect is generated by matching with a multi-iron layer arranged below the MI/NM/MI (or MI/AFI/MI) magnetic sub-valve structure to realize high-efficiency excitation of magnetic sub-flow in the magnetic sub-valve, and finally, a prototype device of a nonvolatile, higher-frequency and lower-power consumption memory structure is realized.
Different from the prior art that the function of the electric control magneton valve is realized by using gradient temperature, the electric control magneton valve structure disclosed by the invention can effectively realize the function of the electric control magneton valve by using the resonant frequency and amplitude of a sound body wave based on sound body wave excitation and matching with voltage control. The FBAR structure is a Bulk Acoustic Wave (BAW) -based resonance technology that converts an electrical signal into an acoustic wave using an inverse piezoelectric effect of a piezoelectric film when a direct current electric field is applied to both ends of a material, thereby forming resonance to generate a ferromagnetic resonance effect to excite a magnetic flux with high efficiency.
Taking an MI/NM/MI magnetic sub-valve structure as an example, different coercive forces are generated by finely regulating the crystal structures of two ferromagnetic nonmetal layers in the MI/NM/MI magnetic sub-valve structure, so that antiparallel relative magnetization orientation is realized; under the parallel and antiparallel configuration, relatively large and small magnetic fluxes can be respectively output outwards, namely the magnetic flux passing through the magnetic flux valve is controlled by the relative orientation of the two ferromagnetic insulating layers to realize the switching action, thereby achieving the storage function. Specifically, the invention uses the acoustic wave to excite the magnetic moment of the MI/NM layer in the lower layer to change (because the acoustic wave is excited, the generated spin wave penetrates MI1 and MI2, but because the propagation loss, the excitation degrees of the two layers are different, and because the propagation directions of the acoustic wave are the same, the excitation effect on the two layers of MI is the same, but the effect degrees are different), the voltage-controlled MI/BFO multiferroic layer exchange bias effect achieves the magnetic moment change (one layer of the three-layer structure MI/NM/MI in the magnetovalve is combined with BFO to form a heterojunction structure, the magnetic moment of the MI layer can achieve the effect of controlling the magnetic moment size and direction of the MI layer film through the exchange bias effect of the heterojunction), so that the relative orientation of the two layers of magnetic moments can be controlled to achieve the magneton valve effect, namely the magneton flow size (the magneton flow is small, meaning that the magneton valve is closed, and vice versa on).
The invention verifies and utilizes the exchange bias effect of the multiferroic material, the multiferroic material has ferroelectricity and ferromagnetism, and the exchange bias effect between the multiferroic material and the magnetic layer is more obvious and easier to regulate and control. The exchange bias effect is provided based on the effect of a ferromagnetic interface and an antiferromagnetic interface, a multiferroic material is used, and the multiferroic material not only has various single ferroicity (such as ferroelectricity and ferromagnetism), but also has the excellent performance of controlling electric polarization through a magnetic field or controlling magnetic polarization through an electric field by the coupling composite synergistic action of the ferroelectricity, namely the exchange bias effect can be better realized by utilizing the ferromagnetism of the multiferroic material, and the electric control function is better realized by utilizing the ferroelectricity of the multiferroic material. The effect of the exchange bias effect heterojunction structure is that the effect of electric field regulation and control of magnetic moment of the MI layer film is achieved through the exchange bias effect of the heterojunction, so that the relative orientation of the upper magnetic moment and the lower magnetic moment is achieved, and the on-off of the magneton valve is achieved.
BiFeO is preferably adopted in the invention3(BFO) is a multiferroic material having two controllable properties at room temperature due to its ordering of ferroelectric and antiferromagnetic structures at room temperature. Because the property of the magnetic valve can generate an electromagnetic coupling effect, namely the internal magnetic moment can be changed along with the change of an external voltage and is applied to the aspect of storage, the magnetic valve can realize an electric control magneton valve structure based on the excitation of sound body waves by matching the magnetic valve with the FBAR, and the FBAR is utilized to adjust the resonant frequency and amplitude and generate a ferromagnetic resonance effect with the multiferroic layer so as to realize the high-efficiency excitation of magneton flow in the magneton valve. The multiferroic layer can be further divided into two layers, different multiferroic materials are adopted to reduce the leakage current of the device and form a multiferroic/ferromagnetic heterojunction functional layer with the magnetic fixed layer, the main pinning function and the electric control function are exerted, and the electric controllability of the device is realized. The invention preferably adopts a layer of Ti or Nb doped BiFeO3Buffer layer and a layer of rare earth element doped BiFeO3An electric control layer; and the appropriate Ti doping amount can make the grain size of BFO smaller and smaller, and is also beneficial to the epitaxial growth of BFO on an electrode layer, namely the grown film has better quality.
Therefore, the electric control magnetic sub-valve structure based on the excitation of the sound wave and the magnetic sub-valve structure, namely the magnetic insulator/metal/magnetic insulator (MI/NM/MI), realize the switching action by electrically adjusting the magnetic sub-flow of the magnetic sub-valve, and further realize the storage function. In the magnetic sub-valve structure, different coercive forces are generated by finely regulating the magnetic moments of the two magnetic nonmetal layers, namely by finely regulating the crystal structures of the two magnetic nonmetal layers, so that antiparallel relative magnetization orientation is realized; the method is characterized in that a sound wave excitation mode is combined with a magneton valve, the magnetic magneton current in a ferromagnetic nonmetal layer is excited by spin waves with the harmonic frequency of the sound wave as a carrier, and the switching storage function is realized by adjusting the size of the magnetic magneton current. According to the room-temperature electronic control magneton valve structure based on acoustic wave excitation, ferromagnetic resonance is realized by adjusting and adjusting resonance frequency and amplitude through FBAR (film bulk acoustic resonator) so as to excite the magnitude of magneton flow in the magneton valve, so that the device is switched on and off, and the storage function is achieved; meanwhile, due to the adoption of a mode of acoustic wave excitation, the device has the excellent characteristics of smaller size, easy integration, high frequency and low power consumption.
Based on the framework and the implementation scheme of the integral prototype device, the acoustic wave excitation-based electronic control magnetic sub-valve prototype device is used as a magnetic sub-core unit device for spin information transfer and logic operation, and compared with the traditional memory device, the magnetic sub-core unit device has the characteristics of lower energy consumption, rewritability, nonvolatility and high frequency. The magneton valve structure can be matched with the existing large-scale integrated circuit process, and is beneficial to the comprehensive integration and wide utilization of future magneton devices, spintronic devices and semiconductor microelectronic devices.
Drawings
FIG. 1 is a schematic diagram of the discrete structure of each layer of the room temperature electronic control magneton valve device based on acoustic wave excitation.
Fig. 2 is a schematic diagram of a typical structure of an FBAR employed in the present invention.
Fig. 3 is a schematic structural diagram of the novel magnetic sub-valve assembly employed in the present invention.
Fig. 4 is a schematic diagram of the acoustic wave excitation magneton valve effect of the present invention.
FIG. 5 shows the anti-spin Hall voltage states of the spin-wave excitation-based magneton valve of the present invention in the parallel and anti-parallel states.
FIG. 6 is a graph of the inverse spin Hall effect voltage versus magnetic field for a spin wave excitation based magneton valve of the present invention.
The meanings of the reference symbols in the figures are as follows: 1 is a substrate, 2 is a bottom electrode, 3 is a multiferroic layer, 4 is a first magnetic insulating layer, 5 is a nonmagnetic metal layer, 6 is a second magnetic insulating layer, 7 is a piezoelectric film, and 8 is an electrode; the structure comprises a film acoustic wave resonator structure, a magneton valve structure and a ferroelectric exchange bias heterojunction structure.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
As shown in FIG. 1, the room temperature electric control magneton valve structure based on acoustic wave excitation mainly comprises three substructures, namely a film acoustic wave resonator structure I, a magneton valve structure II and a ferroelectric exchange bias heterojunction structure III; wherein the content of the first and second substances,
the film bulk acoustic wave resonator structure (i) comprises a piezoelectric film 7 and electrode layers 8 positioned on the upper end face and the lower end face of the piezoelectric film 7 (because the electrode layers 8 correspond to the upper electrode and the lower electrode, the film bulk acoustic wave resonator structure (i) can generate bulk acoustic waves with the propagation direction from top to bottom or from bottom to top, and the propagation direction of the bulk acoustic waves is perpendicular to the film, namely parallel to the vibration direction of the film);
the magneton valve structure II comprises a first magnetic insulating layer 4, a nonmagnetic metal layer 5 and a second magnetic insulating layer 6 which are distributed from top to bottom; the second magnetic insulating layer 6 on the uppermost layer is directly contacted with the electrode layer 8 in the thin film acoustic wave resonator structure (r), and the electrode layer 8 is separately arranged above the second magnetic insulating layer, and is used as an input electrode of the magneton valve structure (r), so that voltage can be applied to the device to adjust and control the exchange bias effect of MI/BFO.
The ferroelectric exchange bias heterojunction structure (c) comprises a multiferroic layer (3) and a bottom electrode (2) which are distributed from top to bottom.
The film acoustic wave resonator structure I, the magneton valve structure II and the ferroelectric exchange bias heterojunction structure III can be positioned and distributed on the substrate 1 from top to bottom in a stacked manner.
The substrate 1 may preferably be a ferroelectric single crystal.
In view of the production of a multiferroic thin film, the substrate is preferably SrTiO3As a substrate. The bottom electrode layer is preferably SrRuO in consideration of lattice matching of the multiferroic layer thin film with the bottom electrode layer3. The bottom electrode layer is deposited on the ferroelectric single crystal substrate, the lattice matching degree between the electrode layer and the multiferroic layer is controlled (the lattice matching degree between the electrode layer and the polycrystalline multiferroic layer can be preferably less than 0.1, namely preferably less than 10%), and the area of the bottom electrode layer is consistent with that of the substrate, and the bottom electrode layer is mainly used as a buffer layer of the electrode layer and the upper multiferroic layer.
The multiferroic layer is prepared on the bottom electrode layer, and in order to reduce the leakage current of the device and realize the electrical controllability of the device, the multiferroic layer is preferably formed by two parts, for example, one layer uses Ti-doped BFO as a buffer layer, and the other layer uses La-doped BFO as an electric control layer. In BFO, because Bi is easy to volatilize and valence state fluctuation of Fe ions can cause large leakage current, and further, the ferroelectric and dielectric properties of the BFO are seriously influenced. Therefore, in order to reduce the leakage current of the device and realize the electric controllability of the device, the multiferroic layer is composed of two parts, one layer uses Ti-doped BFO as a buffer layer, and the other layer uses La-doped BFO as an electric control layer.
The Ti-doped BFO is B-site doped. By replacing part of the Fe ions at position B with cations of higher valency, e.g. Ti4+，Nb5+Partial substitution of Fe by plasma3+Ions (of course, other cations of higher valency may be substituted, although Ti or Nb doping is presently preferred). High-valence cation doping can reduce oxygen vacancy, thereby changing Fe2+Concentration of ions (reduction of oxygen vacancies Fe3+The ions are less oxidized to Fe2+Ions) and thus can effectively reduce leakage current and increase electricityAnd (5) blocking to obtain a saturated hysteresis loop. And with the increase of the Ti content (within 10 percent, namely BiFe)1-xTixO3The value of x in the intermediate is controlled within 10 percent), the crystal structure of BFO gradually changes towards an oblique direction, the grain size is smaller and smaller, and the ferroelectric-paraelectric phase transition temperature (Tc) is gradually reduced. After Ti is doped, the leakage current of the BFO material is reduced, and the remanent polarization value is increased. Therefore, after Ti is doped, the microstructure, the leakage current, the residual polarization and the fatigue of the BFO film are all improved.
The Bi element is easy to volatilize in the preparation process, and the finally obtained product possibly does not meet the expected stoichiometric ratio, while the La, Nd and other rare earth elements are introduced in the invention to inhibit the volatilization of the Bi element, thereby having great effect on improving ferromagnetism and ferroelectricity, reducing leakage current and dielectric loss. And the addition of the rare earth elements can simultaneously improve the ferroelectric and ferromagnetic properties of the BFO phase, and is beneficial to regulating and controlling the interface effect.
On the other hand, the upper and lower magnetic insulating layers of the magneton valve preferably adopt a ferrimagnetic film Y with narrow width of ferromagnetic resonance line, high resistivity and small high-frequency loss3Fe5O12(YIG) higher on-off ratios of the magnetovalve device can be achieved.
Since the magnitude of the magneton-valve ratio mainly depends on the magneton-electron spin conversion efficiency of the magnetic insulator/metal interface, in order to improve the magneton-valve ratio and achieve a higher on-off ratio, the intermediate nonmagnetic metal conductor preferably adopts a nonmagnetic conductor such as Au, Pt or MgO. Besides the components of each structure in the magnetic sub-valve part can be adjusted according to actual requirements, the thickness of each layer structure can be correspondingly adjusted and controlled, so that a better magnetic sub-valve effect is obtained; for example, the specific structure of the magneton valve part can be YIG (20nm) -Au (15nm)/Pt (10nm)/MgO (10nm) -YIG (40nm), so that a relatively obvious magneton valve effect can be obtained, a better magneton valve effect can be achieved by accurately regulating and controlling the thickness of each thin film of the magneton valve, and other magnetic non-metal layers and non-magnetic metal layers can be set by adopting other thicknesses.
The AlN piezoelectric film with large dielectric constant, small temperature coefficient, excellent thermal conductivity, good chemical stability and high longitudinal sound channel transmission speed can be preferably adopted as the piezoelectric film to participate in the construction of the FBAR sound wave resonator, so that the FBAR sound wave resonator can realize good quality factor, resonant frequency and smaller volume.
Example 1:
this example can be prepared by the following steps:
in single crystal SrTiO3(001) Preparing a layer of SrRuO on a substrate by Pulsed Laser Deposition (PLD)3As a bottom electrode.
Preparing a layer of Ti-doped BFO on the bottom electrode by adopting PLD (laser induced chemical vapor deposition) as a buffer layer, wherein the specific doping concentration of Ti doping can be 5 percent (namely, BiFe1-xTixO3Wherein x is 0.05); of course, the doping amount can also be adjusted appropriately to minimize the leakage current of the Ti-doped BFO buffer layer.
A La-doped BFO film is grown to be used as an electric control layer of the device, and the specific doping concentration of the La doping can be 5 percent (namely Bi)1-xLaxFeO3Where x is 0.05), according to the experimental result, the residual polarization Pr value of the material is larger, so that the ferroelectric can have more effective pyroelectric effect or piezoelectric effect after artificial polarization.
And preparing a layer of ferromagnetic film on the surface of the BFO film by adopting a PLD (laser induced deposition)/magnetron sputtering mode to form an MI/BFO heterojunction.
And preparing a non-magnetic interlayer and a magnetic insulating layer on the ferromagnetic thin film by adopting a magnetron sputtering mode to form an MI/NM/MI magnetic sub-valve structure.
A layer of Pt nano film is prepared on the magneton valve structure by adopting a magnetron sputtering method and is used as an electrode layer and a bottom electrode of the FBAR.
And preparing an AlN piezoelectric film on the bottom electrode in a reactive sputtering mode.
A layer of Pt nano film is prepared on the piezoelectric film in a magnetron sputtering mode and is used as a top electrode to form an FBAR structure.
Photolithography is used to prepare the electrode pattern of the entire device.
And finally, preparing an electrode by adopting an electron beam evaporation mode to form a prototype storage device.
FBAR is a Bulk Acoustic Wave (BAW) -based resonance technology that converts electric energy (signal) into an acoustic wave using the inverse piezoelectric effect of a piezoelectric film, thereby forming resonance. As shown in fig. 2, when a direct current electric field is applied to two ends of a material, the deformation of the material changes with the magnitude of the electric field, and when the direction of the electric field is opposite, the direction of the deformation of the material changes, so that vibration is generated, the vibration excites a bulk acoustic wave propagating along the thickness direction of the film, the acoustic wave is transmitted to the interface between the upper electrode and the lower electrode and the air, and is reflected back and forth inside the film to form oscillation, so that the excitation mode based on the bulk acoustic wave is achieved, and compared with a surface acoustic wave resonator (SAW), the vibration occurs in a body cavity of a piezoelectric material, so that the piezoelectric material can bear larger power, and the excitation mode is also one reason that the FBAR technology is superior to the SAW. For example, when an alternating electric field is applied, the direction of deformation of the material changes in a reciprocating manner as the electric field contracts or expands during the positive and negative half cycles. The electrode layers at the two ends of the piezoelectric film are utilized to apply different voltages, and then the regulation and control of the resonant frequency and the amplitude of the acoustic wave can be realized.
The structure of the magneton-valve part is shown in fig. 3, and the voltage measured through the top electrode Pt layer is proportional to the total flux current through the top layer to observe the magneton-valve effect.
The progress in the study of the spin Seebeck effect and the magnetic drag effect have demonstrated that magnetic currents in ferromagnetic insulators can be generated by thermal gradients or electron spin injection.
Description of the magnetic valve effect (as in fig. 4): when the spin wave is excited, the magnetic current in the top magnetic non-metallic layer (the MI layer) comes from two sources. One is generated by acoustic wave excitation and the other is a magnetic current injected from the bottom magnetic non-metallic layer (MI layer). If the magnetization directions of the upper and lower MI layers are parallel, the two magnetic currents are added, and the inverse spin Hall voltage of the two magnetic currents is in a high level state; if the magnetization directions of the upper and lower MI layers are antiparallel, the two magnetic currents are subtracted, and the inverse spin Hall voltage assumes a low state. Therefore, the magnetic sub-valve can control the size of the magnetic sub-flow by controlling the relative magnetization orientation of the two magnetic non-metal layers, thereby realizing the on-off of the device.
The state of the inverse spin hall voltage levels of the magneton valve based on spin wave excitation in different magnetization states (parallel/antiparallel) of the two magnetic non-metal layers is shown in fig. 5. It can be seen from fig. 5 and 6 that the inverse spin hall effect voltage depends on the relative orientation of the magnetizations of the two magnetic insulating layers.
In summary, the embodiment can form an electrically controlled magnetic sub-valve structure which integrates the FBAR and the magnetic sub-valve and takes the acoustic wave as an excitation mode, and form a high-efficiency low-power consumption memory prototype device with practical application value. The storage is realized by using the inverse spin Hall effect as a detection means to detect the switching function of the device.
In addition to the specific materials of the specific magnetic sub-valve portions in the above embodiments, other MI/NM/MI magnetic sub-valve structures may be used, such as other MI/NM/MI magnetic sub-valve structures known in the art. The obvious magneton valve effect in the prior structure also has an MI/AFI/MI three-layer structure (wherein AFI represents an antiferromagnetic insulating layer), such as a YIG/NiO/YIG structure, and the invention is also applicable.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (19)
1. An electric control magneton valve structure based on acoustic wave excitation is characterized by comprising a thin film acoustic wave resonator substructure, a magneton valve substructure and a ferroelectric exchange bias heterojunction substructure which are positioned on a substrate (1) from top to bottom, wherein,
the thin film acoustic bulk wave resonator substructure is used for providing acoustic bulk wave excitation for the magnetic sub-valve substructure, and comprises a piezoelectric film (7) and electrode layers (8) which are positioned at two ends of the piezoelectric film (7) and used for applying voltage to the piezoelectric film (7), and the thin film acoustic bulk wave resonator substructure can generate acoustic bulk waves under the action of the applied voltage and can regulate and control the resonant frequency and amplitude of the acoustic bulk waves through different applied voltages;
the magnetic sub-valve structure is a magnetic sub-valve structure of a magnetic insulator/non-magnetic metal/magnetic insulator and comprises a first magnetic insulating layer (4), a non-magnetic metal layer (5) and a second magnetic insulating layer (6) which are distributed from bottom to top;
the resonance frequency and the amplitude of the generated acoustic wave are regulated and controlled by utilizing the film acoustic wave resonator substructure, and ferromagnetic resonance is realized to excite the size of magnetic sub-flow in the magnetic sub-valve substructure, so that the conduction and the cut-off of the magnetic sub-valve substructure are realized, and the excitation of different magnetic sub-flow sizes of the magnetic sub-valve substructure is realized;
the ferroelectric exchange bias heterojunction substructure and the magneton valve substructure share the second magnetic insulating layer (6), the ferroelectric exchange bias heterojunction substructure further comprises a multiferroic layer (3) and a bottom electrode (2) positioned below the multiferroic layer (3), the multiferroic layer (3) and the second magnetic insulating layer (6) form a heterojunction, the ferroelectric exchange bias heterojunction substructure achieves the effect of regulating and controlling the magnetic moment of the second magnetic insulating layer (6) through the exchange bias effect of the heterojunction, and the relative orientation of the magnetic moments of the first magnetic insulating layer (4) and the second magnetic insulating layer (6) is matched and regulated to realize the conduction and the cut-off of the magneton valve.
2. An electrically controlled photonic valve structure based on acoustic wave excitation according to claim 1, characterised in that in the ferroelectric exchange bias heterojunction substructure the multiferroic layer (3), in particular BiFeO, is present in the ferroelectric exchange bias heterojunction substructure3A multiferroic layer.
3. An electrically controlled magneton valve structure based on acoustic wave excitation according to claim 2, characterized in that the multiferroic layer (3) is a co-used layer of Ti or Nb doped BiFeO3Layer and a layer of rare earth element doped BiFeO3And (3) a layer.
4. An electrically controlled magnetoelectronic valve structure based on acoustic wave excitation according to claim 1, wherein the lattice mismatch between the multiferroic layer (3) and the bottom electrode (2) in the ferroelectric exchange-biased heterojunction substructure is less than 10%.
5. An electrically controlled magneton-valve structure based on acoustic wave excitation according to claim 2, characterized in that the bottom electrode (2) is SrRuO3。
6. An electrically controlled magnetic sub-valve structure based on bulk acoustic wave excitation according to claim 1, wherein in the thin film bulk acoustic wave resonator sub-structure, the piezoelectric film (7) is an AIN piezoelectric film;
the electrode layers (8) are an upper layer and a lower layer and are respectively positioned on the upper surface and the lower surface of the piezoelectric film (7); the thin film bulk acoustic wave resonator substructure is capable of generating bulk acoustic waves with a propagation direction perpendicular to the piezoelectric thin film (7).
7. An electrically controlled magneton-valve structure based on acoustic wave excitation according to claim 1, wherein said magneton-valve substructure is characterized in that said first and second magnetic insulating layers (4, 6) are both Y3Fe5O12A layer;
the nonmagnetic metal layer (5) is a metal single layer or a metal oxide layer containing nonmagnetic metal.
8. An electrically controlled magnetic sub-valve structure based on acoustic wave excitation according to claim 7, characterized in that the non-magnetic metal layer (5) is made of Au or Pt or MgO.
9. An electrically controlled magneton-valve structure based on acoustic wave excitation according to claim 1, wherein the substrate (1) is a ferroelectric single crystal.
10. An electrically controlled magneton-valve structure based on acoustic body wave excitation according to claim 9, characterized in that the substrate (1) is SrTiO3And (3) single crystal.
11. An electric control magneton valve structure based on acoustic wave excitation is characterized by comprising a thin film acoustic wave resonator substructure, a magneton valve substructure and a ferroelectric exchange bias heterojunction substructure which are positioned on a substrate (1) from top to bottom, wherein,
the thin film acoustic bulk wave resonator substructure is used for providing acoustic bulk wave excitation for the magnetic sub-valve substructure, and comprises a piezoelectric film (7) and electrode layers (8) which are positioned at two ends of the piezoelectric film (7) and used for applying voltage to the piezoelectric film (7), and the thin film acoustic bulk wave resonator substructure can generate acoustic bulk waves under the action of the applied voltage and can regulate and control the resonant frequency and amplitude of the acoustic bulk waves through different applied voltages;
the magnetic sub-valve structure is a magnetic sub-valve structure of a magnetic insulator/nonmagnetic metal/magnetic insulator and comprises a first magnetic insulating layer (4), an antiferromagnetic insulating layer and a second magnetic insulating layer (6) which are distributed from bottom to top;
the resonance frequency and the amplitude of the generated acoustic wave are regulated and controlled by utilizing the film acoustic wave resonator substructure, and ferromagnetic resonance is realized to excite the size of magnetic sub-flow in the magnetic sub-valve substructure, so that the conduction and the cut-off of the magnetic sub-valve substructure are realized, and the excitation of different magnetic sub-flow sizes of the magnetic sub-valve substructure is realized;
the ferroelectric exchange bias heterojunction substructure and the magneton valve substructure share the second magnetic insulating layer (6), the ferroelectric exchange bias heterojunction substructure further comprises a multiferroic layer (3) and a bottom electrode (2) positioned below the multiferroic layer (3), the multiferroic layer (3) and the second magnetic insulating layer (6) form a heterojunction, the ferroelectric exchange bias heterojunction substructure achieves the effect of regulating and controlling the magnetic moment of the second magnetic insulating layer (6) through the exchange bias effect of the heterojunction, and the relative orientation of the magnetic moments of the first magnetic insulating layer (4) and the second magnetic insulating layer (6) is matched and regulated to realize the conduction and the cut-off of the magneton valve.
12. Electronically controlled magneton-valve structure based on acoustic wave excitation according to claim 11, characterized in that in the ferroelectric exchange bias heterojunction substructure the multiferroic layer (3), in particular BiFeO, is present3A multiferroic layer.
13. The acoustic-based body of claim 12The wave-excited electronic control magneton valve structure is characterized in that the multiferroic layer (3) is a layer of Ti or Nb doped BiFeO used in cooperation3Layer and a layer of rare earth element doped BiFeO3And (3) a layer.
14. An electrically controlled magnetoelectronic valve structure based on acoustic wave excitation according to claim 11, wherein the lattice mismatch between the multiferroic layer (3) and the bottom electrode (2) in the ferroelectric exchange-biased heterojunction substructure is less than 10%.
15. An electrically controlled magneton-valve structure based on acoustic body wave excitation according to claim 12, characterized in that the bottom electrode (2) is SrRuO3。
16. An electrically controlled magnetic sub-valve structure based on bulk acoustic wave excitation according to claim 11, wherein in the thin film bulk acoustic wave resonator sub-structure, the piezoelectric film (7) is an AIN piezoelectric film;
the electrode layers (8) are an upper layer and a lower layer and are respectively positioned on the upper surface and the lower surface of the piezoelectric film (7); the thin film bulk acoustic wave resonator substructure is capable of generating bulk acoustic waves with a propagation direction perpendicular to the piezoelectric thin film (7).
17. An electrically controlled magnetorestrictive valve structure based on acoustic body wave excitation according to claim 12, characterized in that said magnetorestrictive valve structure is such that said first magnetic insulating layer (4) and said second magnetic insulating layer (6) are both Y3Fe5O12A layer;
the antiferromagnetic insulating layer is NiO.
18. An electrically controlled magneton-valve structure based on acoustic wave excitation according to claim 11, wherein the substrate (1) is a ferroelectric single crystal.
19. An electrically controlled magneton-valve structure based on acoustic body wave excitation according to claim 18, characterized in that the substrate (1) is SrTiO3And (3) single crystal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910550803.7A CN110299446B (en) | 2019-06-24 | 2019-06-24 | Electric control magneton valve structure based on acoustic wave excitation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910550803.7A CN110299446B (en) | 2019-06-24 | 2019-06-24 | Electric control magneton valve structure based on acoustic wave excitation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110299446A CN110299446A (en) | 2019-10-01 |
| CN110299446B true CN110299446B (en) | 2021-03-26 |
Family
ID=68028591
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910550803.7A Active CN110299446B (en) | 2019-06-24 | 2019-06-24 | Electric control magneton valve structure based on acoustic wave excitation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110299446B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1687729A (en) * | 2005-06-09 | 2005-10-26 | 上海交通大学 | Method for manufacturing force-sensing parts based on micro electromechanical system |
| CN101599340A (en) * | 2009-04-08 | 2009-12-09 | 南京航空航天大学 | Direct magnetic coupling preparation method of magneto strictive multiplayer film |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100224912A1 (en) * | 2008-11-10 | 2010-09-09 | Varshni Singh | Chromium doped diamond-like carbon |
-
2019
- 2019-06-24 CN CN201910550803.7A patent/CN110299446B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1687729A (en) * | 2005-06-09 | 2005-10-26 | 上海交通大学 | Method for manufacturing force-sensing parts based on micro electromechanical system |
| CN101599340A (en) * | 2009-04-08 | 2009-12-09 | 南京航空航天大学 | Direct magnetic coupling preparation method of magneto strictive multiplayer film |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110299446A (en) | 2019-10-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Yan et al. | Electric‐field‐controlled antiferromagnetic spintronic devices | |
| Hu et al. | Electric-field control of strain-mediated magnetoelectric random access memory | |
| Moriyama et al. | Anti-damping spin transfer torque through epitaxial nickel oxide | |
| Yu et al. | Magnetization switching through spin-Hall-effect-induced chiral domain wall propagation | |
| Pertsev et al. | Resistive switching via the converse magnetoelectric effect in ferromagnetic multilayers on ferroelectric substrates | |
| Kleemann | Multiferroic and magnetoelectric nanocomposites for data processing | |
| Wu et al. | Electrical and mechanical manipulation of ferromagnetic properties in polycrystalline nickel thin film | |
| Shao et al. | Néel spin currents in antiferromagnets | |
| CN105449097B (en) | Double magnetism potential barrier tunnel knots and the spintronics devices including it | |
| Guo et al. | Electrical field control of non-volatile 90° magnetization switching in epitaxial FeSi films on (001) 0.7 [Pb (Mg1/3Nb2/3) O3]-0.3 [PbTi0. 3O3] | |
| Gradauskaite et al. | Multiferroic heterostructures for spintronics | |
| CN111384235B (en) | Magnetic tunnel junction and NSOT-MRAM device based on magnetic tunnel junction | |
| Channagoudra et al. | Magnetoelectric coupling in ferromagnetic/ferroelectric heterostructures: A survey and perspective | |
| JP4304688B2 (en) | Spin filter effect element and magnetic device using the same | |
| Zhang et al. | Control of magnetic anisotropy in epitaxial Co2MnAl thin films through piezo-voltage-induced strain | |
| Pan et al. | Room-temperature orbit-transfer torque enabling van der Waals magnetoresistive memories | |
| Zhang et al. | Epitaxial integration of a perpendicularly magnetized ferrimagnetic metal on a ferroelectric oxide for electric-field control | |
| CN110299446B (en) | Electric control magneton valve structure based on acoustic wave excitation | |
| Gong et al. | A new pathway towards all-electric spintronics: electric-field control of spin states through surface/interface effects | |
| Samanta et al. | Tunneling magnetoresistance in magnetic tunnel junctions with a single ferromagnetic electrode | |
| Useinov et al. | Controlling the spin-torque efficiency with ferroelectric barriers | |
| Rizwan et al. | Piezoelectric enhancement of giant magnetoresistance in spin-valves with different magnetic anisotropies | |
| Merodio et al. | Electric field control of the resistance of multiferroic tunnel junctions with magnetoelectric antiferromagnetic barriers | |
| Han et al. | Fabrication and characterization of a magnetoelectric memory cell of 50Ba (Zr0. 2Ti0. 8) O3–50Ba0. 7Ca0. 3TiO3/Fe70Ga30 | |
| Yang et al. | Electric field-controlled magnetization in bilayered magnetic films for magnetoelectric memory |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |