WO2022111483A1

WO2022111483A1 - Magnetic tunnel junction free layer, and magnetic tunnel junction structure having same

Info

Publication number: WO2022111483A1
Application number: PCT/CN2021/132536
Authority: WO
Inventors: 简红; 宫俊录; 孙一慧; 孟凡涛
Original assignee: 浙江驰拓科技有限公司
Priority date: 2020-11-26
Filing date: 2021-11-23
Publication date: 2022-06-02
Also published as: CN114551716A

Abstract

Provided are a magnetic tunnel junction free layer, and a magnetic tunnel junction structure having same. The magnetic tunnel junction free layer comprises a first magnetic composite layer, an antiferromagnetic spacer structure and a second magnetic composite layer, which are sequentially stacked in a first direction, wherein under the action of the antiferromagnetic spacer structure, the first magnetic composite layer and the second magnetic composite layer are antiferromagnetically coupled, and the magnetization directions thereof are opposite each other. Since multiple magnetic composite layers are used in the structure, the overall thickness of the magnetic layers increases while the magnetization directions are controlled to be perpendicular to a thin film interface, thereby improving the data retention of a device. In addition, in order to reduce a write current, the structure makes the magnetization directions of different magnetic composite layers become opposite to each other, and the total magnetic moment of the entire structure is reduced, thereby reducing the write current and achieving high endurance of the device. Moreover, by means of the structure, a high TMR can be obtained, and the data read speed is improved.

Description

Magnetic tunnel junction free layer and magnetic tunnel junction structure having the same

The present disclosure takes the patent document filed on November 26, 2020 with application number 202011349124.2 and titled “Magnetic Tunnel Junction Free Layer and Magnetic Tunnel Junction Structure Therewith” as a priority document, the entire contents of which are incorporated by reference in this disclosure.

technical field

The present disclosure relates to the technical field of magnetic tunnel junctions, and in particular, to a magnetic tunnel junction free layer and a magnetic tunnel junction structure having the same.

Background technique

Spin Transfer Torque Magnetic Random Access Memory (STT-MRAM for short) is a new type of non-volatile memory whose core storage unit is a magnetic tunnel junction (MTJ) structure. A typical MTJ structure mainly consists of a pinned layer, a barrier layer and a free layer. The pinned layer is also called the reference layer, and its magnetization direction remains unchanged, and only the magnetization direction of the free layer is changed to make it the same or opposite to the pinned layer. The MTJ structure relies on the quantum tunneling effect to allow electrons to pass through the barrier layer. The tunneling probability of polarized electrons and the relative magnetization directions of the pinned and free layers are related. When the magnetization directions of the pinned layer and the free layer are the same, the tunneling probability of polarized electrons is high, and the MTJ structure exhibits a low resistance state (Rp) at this time; when the magnetization directions of the pinned layer and the free layer are opposite, The tunneling probability of polarized electrons is low, and at this time, the MTJ structure exhibits a high resistance state (Rap). The MRAM uses the Rp state and the Rap state of the MTJ structure to represent the logical states "1" and "0" respectively, thereby realizing data storage. The tunneling magnetoresistance value is expressed as: TMR=100%×(R _ap −R _p )/R _p .

STT-MRAM utilizes the spin transfer torque effect (STT) of current to write to MRAM. When the spin-polarized current passes through a magnetic film, the polarization current will exchange and interact with the local electrons of the magnetic film, thereby exerting a torque on the local magnetic moment of the magnetic film, making it tend to interact with the spin-polarized film. The currents are polarized in the same direction, a phenomenon known as the spin transfer torque effect (STT effect). A polarization current opposite to its magnetization direction is applied to the magnetic film. When the intensity of the polarization current exceeds a certain threshold, the magnetic moment of the magnetic film itself can be reversed. Using the spin transfer torque effect, the magnetization direction of the free layer of the MTJ structure can be made parallel or antiparallel to the magnetization direction of the pinned layer, thereby realizing the "write" operation.

MRAM applications require the MTJ structure to have high endurance and data retention at the same time. To obtain good data retention, the free layer of the MTJ structure requires a high perpendicular magnetic anisotropy energy. Generally, the higher the perpendicular magnetic anisotropy energy of the free layer, the greater the required write current. Since the current needs to pass through the barrier layer during the writing process of STT-MRAM, after the MTJ structure is written multiple times, the barrier layer will break down, resulting in device failure. The larger the write current required by the device, the less conducive to the improvement of the resistance to erasing and writing.

Therefore, the MTJ structure in the prior art urgently needs to solve the problem of maintaining high data retention capability and high resistance to erasing and writing at the same time.

SUMMARY OF THE INVENTION

The main purpose of the present disclosure is to provide a magnetic tunnel junction free layer and a magnetic tunnel junction structure having the same, so as to solve the problem that the magnetic tunnel junction structure in the prior art is difficult to maintain high data storage capability and high resistance to erasing and writing at the same time.

In order to achieve the above object, according to one aspect of the present disclosure, there is provided a magnetic tunnel junction free layer, comprising a first magnetic composite layer, an antiferromagnetic spacer structure and a second magnetic composite layer sequentially stacked along a first direction. Under the action of the ferromagnetic spacer structure, the first magnetic composite layer and the second magnetic composite layer are antiferromagnetically coupled, and the magnetization directions are opposite.

Optionally, the first magnetic composite layer includes a first ferromagnetic layer, a first spacer layer and a second ferromagnetic layer sequentially stacked along a first direction, and the magnetization directions of the first ferromagnetic layer and the second ferromagnetic layer are the same, And the magnetization direction is perpendicular to the film interface.

Optionally, the material of the first spacer layer includes any one of Ta, Mo, W, Ti, Hf, Zr, Nb, TaN, TiN, NbN, TaB, TiB, MoB, HfB, ZrB, NbN and WB or variety.

Optionally, the second magnetic composite layer includes a third ferromagnetic layer, a second spacer layer and a fourth ferromagnetic layer sequentially stacked along the first direction, and the magnetization directions of the third ferromagnetic layer and the fourth ferromagnetic layer are the same, And the magnetization direction is perpendicular to the film interface.

Optionally, the material of the second spacer layer includes any one of Ta, Mo, W, Ti, Hf, Zr, Nb, TaN, TiN, NbN, TaB, TiB, MoB, HfB, ZrB, NbN and WB or variety.

Optionally, the antiferromagnetic spacer structure includes a spacer film and an antiferromagnetic coupling layer sequentially stacked along a first direction or a direction opposite to the first direction, the spacer film is a non-magnetic spacer layer, or the spacer film includes a spacer film along the first direction. In the stacked multilayer spacer films, at least one layer of the spacer films is a non-magnetic spacer film.

Optionally, the non-magnetic spacer layer or the non-magnetic spacer film is an oxide, preferably the material of the non-magnetic spacer layer or the non-magnetic spacer film includes MgO, AlO _x , MgAlO _x , TiO _x , TaO _x , GaO _x and FeO any one or more of _x .

Optionally, the material of the antiferromagnetic coupling layer includes any one or more of Ru, Ir and Cr.

Optionally, the magnetic tunnel junction free layer further includes an enhancement layer located on the side of the second magnetic composite layer away from the antiferromagnetic spacer structure, preferably the enhancement layer is an oxide, and more preferably the material of the enhancement layer includes MgO, AlO _x , MgAlO _x Any one or more of , TiO _x , TaO _x , GaO _x and FeO _x .

According to another aspect of the present disclosure, a magnetic tunnel junction is provided, comprising a reference layer, a barrier layer and a free layer stacked in sequence, where the free layer is the above-mentioned magnetic tunnel junction free layer.

By applying the technical solutions of the present disclosure, a magnetic tunnel junction free layer is provided, which includes a reference layer, a barrier layer, and a free layer that are sequentially stacked, and the free layer includes a first magnetic composite layer that is sequentially stacked along a direction away from the barrier layer, The antiferromagnetic spacer structure and the second magnetic composite layer, the first magnetic composite layer and the second magnetic composite layer are antiferromagnetically coupled, and the magnetization directions are opposite. Since the above structure adopts a multi-layer magnetic composite layer, the overall thickness of the magnetic layer is increased while the magnetization direction is controlled to be perpendicular to the film interface, thereby increasing the data retention capability of the device. In addition, in order to reduce the write current, the above structure makes the magnetization directions of the different magnetic composite layers opposite to reduce the total magnetic moment of the overall structure, thereby reducing the write current and achieving high resistance to erasing and writing of the device. In addition, the structure can obtain higher TMR, which improves the data reading speed.

Description of drawings

The accompanying drawings that constitute a part of the present disclosure are used to provide further understanding of the present disclosure, and the exemplary embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure. In the attached image:

FIG. 1 shows a schematic cross-sectional structure diagram of a magnetic tunnel junction free layer according to an embodiment of the present disclosure;

FIG. 2 shows a schematic cross-sectional structure diagram of another magnetic tunnel junction free layer provided according to an embodiment of the present disclosure;

FIG. 3 shows a schematic cross-sectional structure diagram of a magnetic tunnel junction having the magnetic tunnel junction free layer shown in FIG. 1; and

FIG. 4 shows a schematic cross-sectional structure diagram of a magnetic tunnel junction having the magnetic tunnel junction free layer shown in FIG. 2 .

Wherein, the above-mentioned drawings include the following reference signs:

10, artificial antiferromagnet; 20, structural transition layer; 30, reference layer; 40, barrier layer; 50, first magnetic composite layer; 510, first ferromagnetic layer; 520, first spacer layer; 530, first Two ferromagnetic layers; 60, antiferromagnetic spacer structure; 610, spacer film; 620, antiferromagnetic coupling layer; 70, second magnetic composite layer; 710, third ferromagnetic layer; 720, second spacer layer; 730 , the fourth ferromagnetic layer; 80, the enhancement layer.

Detailed ways

It should be noted that the embodiments of the present disclosure and the features of the embodiments may be combined with each other under the condition of no conflict. The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

In order to make those skilled in the art better understand the solutions of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only Embodiments are part of the present disclosure, but not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present disclosure.

It should be noted that the terms "first", "second" and the like in the description and claims of the present disclosure and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances for the embodiments of the present disclosure described herein. Furthermore, the terms "comprising" and "having" and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

As described in the background of the present application, the MTJ structure in the prior art needs to solve the problem of maintaining high data retention capability and high resistance to erasing and writing at the same time. In order to solve the above-mentioned technical problems, the applicant of the present disclosure provides a magnetic tunnel junction free layer, which includes a first magnetic composite layer 50, an antiferromagnetic spacer structure 60 and a second magnetic composite layer sequentially stacked along a first direction 70. Under the action of the antiferromagnetic spacer structure 60, the first magnetic composite layer 50 and the second magnetic composite layer 70 are antiferromagnetically coupled, and the magnetization directions are opposite.

Since the above-mentioned magnetic tunnel junction free layer adopts a multi-layer magnetic composite layer, the overall thickness of the magnetic layer is increased while the magnetization direction is controlled to be perpendicular to the film interface, thereby increasing the data retention capability of the device. In addition, in order to reduce the writing current, the above-mentioned antiferromagnetic spacer structure makes the magnetization directions of different magnetic composite layers opposite, which reduces the total magnetic moment of the overall structure, thereby reducing the writing current and achieving high resistance to erasing and writing of the device. In addition, the magnetic tunnel junction free layer can obtain higher TMR and improve the data reading speed.

In the above-mentioned magnetic tunnel junction free layer of the present disclosure, the first magnetic composite layer 50 may include a first ferromagnetic layer 510, a first spacer layer 520 and a second ferromagnetic layer 530 sequentially stacked along a first direction, the first ferromagnetic layer The magnetization directions of the magnetic layer 510 and the second ferromagnetic layer 530 are the same, and the magnetization directions are both perpendicular to the film interface, as shown in FIG. 1 and FIG. 2 .

The first ferromagnetic layer 510 and the second ferromagnetic layer 530 are both ferromagnetic or ferrimagnetic materials, preferably, the materials of the first ferromagnetic layer 510 and the second ferromagnetic layer 530 are independently selected from Co, Fe , any one or more of Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, CoFeNi, CoFeB, NiFeB, CoNiB, CoFeNiB, FePt, FePd, CoPt, CoPd, CoFePt, CoFePd, FePtPd, CoPtPd and CoFePtPd , in order to achieve a strong magnetization effect.

Preferably, the material of the first spacer layer 520 includes any one of Ta, Mo, W, Ti, Hf, Zr, Nb, TaN, TiN, NbN, TaB, TiB, MoB, HfB, ZrB, NbN and WB or more. The above materials can ensure that the first ferromagnetic layer 510 and the second ferromagnetic layer 530 on both sides of the first spacer layer 520 realize interlayer ferromagnetic coupling, and the magnetic moment of the magnetic layer can be synchronously reversed with the external field or external current. The interface between the layer 520 and the magnetic layers on both sides can enhance the perpendicular magnetic anisotropy of the free layer, improve the interface characteristics of the free layer, and further improve the performance of the MTJ device.

In the above-mentioned magnetic tunnel junction free layer of the present disclosure, the second magnetic composite layer 70 may include a third ferromagnetic layer 710 , a second spacer layer 720 and a fourth ferromagnetic layer 730 sequentially stacked along the first direction, the third ferromagnetic layer The magnetization directions of the magnetic layer 710 and the fourth ferromagnetic layer 730 are the same, and the magnetization directions are both perpendicular to the film interface, as shown in FIG. 1 and FIG. 2 .

The third ferromagnetic layer 710 and the fourth ferromagnetic layer 730 are both ferromagnetic or ferrimagnetic materials, preferably, the materials of the third ferromagnetic layer 710 and the fourth ferromagnetic layer 730 are independently selected from Co, Fe , any one or more of Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, CoFeNi, CoFeB, NiFeB, CoNiB, CoFeNiB, FePt, FePd, CoPt, CoPd, CoFePt, CoFePd, FePtPd, CoPtPd and CoFePtPd .

Preferably, the material of the second spacer layer 720 includes any one of Ta, Mo, W, Ti, Hf, Zr, Nb, TaN, TiN, NbN, TaB, TiB, MoB, HfB, ZrB, NbN and WB or variety. The above-mentioned materials can ensure that the third ferromagnetic layer 710 and the fourth ferromagnetic layer 730 on both sides of the second spacer layer 720 realize interlayer ferromagnetic coupling, and the magnetic moment of the magnetic layer can be synchronously reversed with the external field or external current. In addition, the second spacer The interface between the layer 720 and the magnetic layers on both sides can enhance the perpendicular magnetic anisotropy of the free layer, improve the interface characteristics of the free layer, and further improve the performance of the MTJ device.

In the above-mentioned magnetic tunnel junction free layer of the present disclosure, the antiferromagnetic spacer structure 60 enables the first magnetic composite layer 50 and the second magnetic composite layer 70 to be antiferromagnetically coupled, and the magnetization directions are opposite. In a preferred implementation In this manner, the antiferromagnetic spacer structure 60 includes a spacer film 610 and an antiferromagnetic coupling layer 620 sequentially stacked along a first direction, as shown in FIG. 1 .

In another preferred embodiment, the antiferromagnetic spacer structure 60 includes a spacer film 610 and an antiferromagnetic coupling layer 620 sequentially stacked in a direction opposite to the first direction, as shown in FIG. 2 .

The above-mentioned spacer film 610 may be a single-layer non-magnetic spacer film, or may include multiple layers of spacer sub-films stacked along the first direction, and at least one layer of the spacer sub-films is a non-magnetic spacer film.

In order to improve the perpendicular magnetic anisotropy of the first magnetic composite layer 50, preferably, the non-magnetic spacer film or the non-magnetic spacer film is an oxide; more preferably, the above-mentioned non-magnetic spacer layer or non-magnetic spacer film The material includes any one or more of MgO, AlO _x , MgAlO _x , TiO _x , TaO _x , GaO _x and FeO _x .

In order to make the first magnetic composite layer 50 and the second magnetic composite layer 70 be antiferromagnetically coupled, and the magnetization directions are opposite, the material of the above-mentioned antiferromagnetic coupling layer 620 may include any one or more of Ru, Ir and Cr, However, it is not limited to the above-mentioned preferred types, and those skilled in the art can reasonably select the types of the above-mentioned antiferromagnetic coupling layers 620 according to the prior art.

The magnetic tunnel junction free layer of the present disclosure may further include an enhancement layer 80 on the side of the second magnetic composite layer 70 away from the antiferromagnetic spacer structure 60 . As shown in FIGS. 1 and 2 , the enhancement layer 80 can enhance the second magnetic composite layer 70 The perpendicular magnetic anisotropy energy of the magnetic composite layer 70 .

Preferably, the reinforcing layer 80 is an oxide, and more preferably, the material of the reinforcing layer 80 includes any one or more of MgO, AlO _x , MgAlO _x , TiO _x , TaO _x , GaO _x and FeO _x .

According to another aspect of the present disclosure, a magnetic tunnel junction is also provided, including a reference layer 30 , a barrier layer 40 and the above-mentioned magnetic tunnel junction free layer stacked in sequence, as shown in FIGS. 3 and 4 .

Since the free layer in the above-mentioned magnetic tunnel junction adopts a multi-layer magnetic composite layer, the overall thickness of the magnetic layer is increased while the magnetization direction is controlled to be perpendicular to the film interface, thereby increasing the data retention capability of the device. In addition, in order to reduce the writing current, the above-mentioned antiferromagnetic spacer structure makes the magnetization directions of different magnetic composite layers opposite, which reduces the total magnetic moment of the overall structure, thereby reducing the writing current and achieving high resistance to erasing and writing of the device.

In a preferred embodiment, the above-mentioned magnetic tunnel junction structure of the present disclosure further includes an artificial antiferromagnet 10 and a structural transition layer 20 sequentially stacked along the side of the reference layer 30 away from the barrier layer 40 , as shown in FIG. 3 and FIG. 4 shown. The above-mentioned artificial antiferromagnet 10 is used to increase the flip field of the reference layer 30, so that the magnetization direction of the reference layer remains unchanged during the writing process of the device, and only the magnetization direction of the free layer is changed. In addition, the artificial antiferromagnetic structure can reduce the free layer. to avoid the instability of the free layer in a certain magnetization direction; the above-mentioned structural transition layer 20 is used for the structural transition between the artificial antiferromagnet 10 and the reference layer 30, and the artificial antiferromagnet 10 is usually (111) In order to achieve high TMR, the reference layer 30 needs to achieve the (001) crystal orientation, so an amorphous transition layer is added between the two, so that the artificial antiferromagnet 10 and the reference layer 30 can each achieve the best crystal orientation. orientation.

The beneficial effects of the present application will be further described below in conjunction with the examples and comparative examples.

The magnetic layers and spacer films of the following embodiments are all prepared by physical vapor deposition process. Target materials or raw materials of specific components are selected, and the gas flow rate, deposition power and deposition time of the deposition process are adjusted to obtain the corresponding material composition. Layer structure of corresponding thickness.

Example 1

The free layer provided in this embodiment includes a first ferromagnetic layer 510, a first spacer layer 520, a second ferromagnetic layer 530, a spacer film 610, an antiferromagnetic coupling layer 620, a third ferromagnetic layer 710, a Two spacer layers 720 and a fourth ferromagnetic layer 730 . The first ferromagnetic layer 510 , the second ferromagnetic layer 530 , the third ferromagnetic layer 710 and the fourth ferromagnetic layer 730 are all CoFeB alloys with a thickness of 1 nm; the first spacer layer 520 and the second spacer layer 720 Both are W, and the thickness is 0.3 nm; the spacer film 610 is a single-layer non-magnetic spacer film, the material is MgO, and the thickness is 1 nm; the antiferromagnetic coupling layer 620 is Ru, and the thickness is 1 nm.

Example 2

The free layer provided in this embodiment includes a first ferromagnetic layer 510, a first spacer layer 520, a second ferromagnetic layer 530, an antiferromagnetic coupling layer 620, a spacer film 610, a third ferromagnetic layer 710, a Two spacer layers 720 and a fourth ferromagnetic layer 730 . The first ferromagnetic layer 510 , the second ferromagnetic layer 530 , the third ferromagnetic layer 710 and the fourth ferromagnetic layer 730 are all CoFeB alloys with a thickness of 1 nm; the first spacer layer 520 and the second spacer layer 720 Both are W, and the thickness is 0.3 nm; the spacer film 610 is a single-layer non-magnetic spacer film, the material is MgO, and the thickness is 1.2 nm; the antiferromagnetic coupling layer 620 is Ru, and the thickness is 0.8 nm.

Example 3

The free layer provided in this embodiment includes a first ferromagnetic layer 510, a first spacer layer 520, a second ferromagnetic layer 530, a spacer film 610, an antiferromagnetic coupling layer 620, a third ferromagnetic layer 710, a The second spacer layer 720 , the fourth ferromagnetic layer 730 and the enhancement layer 80 . The first ferromagnetic layer 510 , the second ferromagnetic layer 530 , the third ferromagnetic layer 710 and the fourth ferromagnetic layer 730 are all CoFeB alloys with a thickness of 1 nm; the first spacer layer 520 and the second spacer layer 720 Both are W, with a thickness of 0.3 nm; the spacer film 610 is a single-layer non-magnetic spacer film, made of MgO, with a thickness of 1.3 nm; the antiferromagnetic coupling layer 620 is Ru, with a thickness of 0.5 nm; the enhancement layer is MgAl ₂ O ₄ , with a thickness of 1.3.nm.

Example 4

The magnetic tunnel junction provided in this embodiment includes a reference layer 30, a barrier layer 40, and the free layer in Embodiment 1, which are stacked in sequence. The material of the reference layer 30 is CoFeB with a thickness of 1 nm; the material of the barrier layer 40 is MgO , with a thickness of 1 nm.

Example 5

The magnetic tunnel junction provided in this embodiment includes a reference layer 30, a barrier layer 40, and the free layer in Embodiment 2, which are stacked in sequence. The material of the reference layer 30 is CoFeB with a thickness of 1 nm; the material of the barrier layer 40 is MgO , with a thickness of 1 nm.

Example 6

The magnetic tunnel junction provided in this embodiment includes a reference layer 30, a barrier layer 40, and the free layer in Embodiment 3 that are stacked in sequence. The material of the reference layer 30 is CoFeB with a thickness of 1 nm; the material of the barrier layer 40 is MgO , with a thickness of 1 nm.

Example 7

The magnetic tunnel junction provided in this embodiment includes an artificial antiferromagnet 10 , a structural transition layer 20 , a reference layer 30 , a barrier layer 40 , and the free layer in Embodiment 1, which are stacked in sequence. Wherein, the material of the artificial antiferromagnet 10 is (Co0.5/Pt0.5)7/Ru0.45/(Co0.5/Pt0.5)3, the thickness is in nm, and the numbers outside the parentheses are the repetition of the Co/Pt structure The material of the structural transition layer 20 is Ta with a thickness of 0.3 nm; the material of the reference layer 30 is CoFeB with a thickness of 1 nm; the material of the barrier layer 40 is MgO with a thickness of 1 nm.

Comparative Example 1

The magnetic tunnel junction provided in this embodiment includes a reference layer, a barrier layer, and a free layer that are stacked in sequence, and the free layer includes a stacked first magnetic layer, a non-magnetic intermediate layer, and a second magnetic layer. The first magnetic layer and the second magnetic layer are CoFeB alloys with a thickness of 1 nm; the non-magnetic intermediate layer is W with a thickness of 0.3 nm.

The TMR, data retention index (Delta), and endurance (endurance) index of the MTJ devices including the magnetic tunnel junctions in each embodiment of the present application and each comparative example are respectively tested, and the test results are shown in the following table.

Table 1

//	TMRTMR	数据保持指标data retention indicator	耐擦写能力Durability
实施例4Example 4	200％200%	113113	1E71E7
实施例5Example 5	200％200%	115115	2E82E8
实施例6Example 6	210％210%	125125	3E83E8
实施例7Example 7	205％205%	113113	3E73E7
对比例1Comparative Example 1	190％190%	6565	1E61E6

From the above description, it can be seen that the above-mentioned embodiments of the present disclosure achieve the following technical effects:

1. Since the above-mentioned magnetic tunnel junction free layer adopts a multi-layer magnetic composite layer, while controlling the magnetization direction to be perpendicular to the film interface, the overall thickness of the magnetic layer is increased, thereby increasing the data retention capability of the device;

2. In order to reduce the writing current, the above-mentioned antiferromagnetic spacer structure makes the magnetization directions of different magnetic composite layers opposite, reducing the total magnetic moment of the overall structure, thereby reducing the writing current, and achieving high resistance to erasing and writing of the device;

3. The above magnetic tunnel junction can obtain higher TMR and improve the data reading speed.

The above descriptions are only preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

A magnetic tunnel junction free layer, comprising a first magnetic composite layer (50), an antiferromagnetic spacer structure (60), and a second magnetic composite layer (70) sequentially stacked along a first direction, wherein the antiferromagnetic Under the action of the magnetic spacer structure (60), the first magnetic composite layer (50) and the second magnetic composite layer (70) are antiferromagnetically coupled, and the magnetization directions are opposite.
The magnetic tunnel junction free layer according to claim 1, wherein the first magnetic composite layer (50) comprises a first ferromagnetic layer (510) and a first spacer layer (520) sequentially stacked along the first direction ) and the second ferromagnetic layer (530), the magnetization directions of the first ferromagnetic layer (510) and the second ferromagnetic layer (530) are the same, and the magnetization directions are both perpendicular to the film interface.
The magnetic tunnel junction free layer according to claim 2, wherein the material of the first spacer layer (520) comprises Ta, Mo, W, Ti, Hf, Zr, Nb, TaN, TiN, NbN, TaB, TiB , any one or more of MoB, HfB, ZrB, NbN and WB.
The magnetic tunnel junction free layer according to claim 1, wherein the second magnetic composite layer (70) comprises a third ferromagnetic layer (710) and a second spacer layer (720) sequentially stacked along the first direction ) and the fourth ferromagnetic layer (730), the magnetization directions of the third ferromagnetic layer (710) and the fourth ferromagnetic layer (730) are the same, and the magnetization directions are both perpendicular to the film interface.
The magnetic tunnel junction free layer according to claim 4, wherein the material of the second spacer layer (720) comprises Ta, Mo, W, Ti, Hf, Zr, Nb, TaN, TiN, NbN, TaB, TiB , any one or more of MoB, HfB, ZrB, NbN and WB.
The magnetic tunnel junction free layer according to any one of claims 1 to 5, wherein the antiferromagnetic spacer structures (60) comprise sequential stacking in the first direction or a direction opposite to the first direction A spacer film (610) and an antiferromagnetic coupling layer (620) of Sub-film, at least one layer of the spacer film (610) is a non-magnetic spacer film.
The magnetic tunnel junction free layer according to claim 6, wherein the non-magnetic spacer layer or the non-magnetic spacer film is an oxide, preferably the material of the non-magnetic spacer layer or the non-magnetic spacer film Any one or more of MgO, AlO x , MgAlO x , TiO x , TaO x , GaO x and FeO x are included.
The magnetic tunnel junction free layer according to claim 6, wherein the material of the antiferromagnetic coupling layer (620) comprises any one or more of Ru, Ir and Cr.
The magnetic tunnel junction free layer according to any one of claims 1 to 5, wherein the magnetic tunnel junction free layer further comprises a magnetic tunnel junction free layer located at the second magnetic composite layer (70) away from the antiferromagnetic spacer structure ( 60) the reinforcing layer (80) on one side, preferably the reinforcing layer (80) is an oxide, more preferably the material of the reinforcing layer (80) includes MgO, AlO x , MgAlO x , TiO x , TaO x , GaO Any one or more of x and FeO x .
A magnetic tunnel junction, comprising a reference layer (30), a barrier layer (40) and a free layer stacked in sequence, wherein the free layer is the magnetic tunnel junction free layer according to any one of claims 1 to 9 Floor.