Low-temperature annealing method for improving spin injection efficiency of two-dimensional magnetic material interface

Abstract

The invention discloses a low-temperature annealing method for improving the interface spin injection efficiency of a two-dimensional magnetic material, and relates to the technical field of two-dimensional magnetic material preparation. The preparation method comprises the following steps: S1, constructing a Fe3GaTe2 / Pt heterostructure; and S2, carrying out annealing treatment on the Fe3GaTe2 / Pt heterostructure. According to the method, the Fe3GaTe2 / Pt heterojunction interface is optimized through ultrahigh vacuum annealing, so that the spin injection efficiency and the magnetization turnover rate are effectively improved; according to the method, the annealing temperature of 100 DEG C is adopted and is far lower than the temperature in the annealing process in the prior art, and the annealing process has the characteristics of simplicity in operation, easiness in implementation, low energy consumption and the like, and can be applied to the semiconductor industry; according to the method, the current-driven magnetization turnover rate in the Fe3GaTe2 / Pt heterostructure subjected to low-temperature ultrahigh vacuum annealing treatment exceeds 95%, deterministic turnover is achieved, and the current-driven magnetization turnover rate is improved by more than 6 times compared with that of a sample before annealing.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of two-dimensional magnetic materials, and specifically to a low-temperature annealing method for improving the interfacial spin injection efficiency of two-dimensional magnetic materials. Background Art

[0002] Due to the characteristics of atomic-level flat interfaces, easy heterostructure construction, and flexible stacking methods, two-dimensional magnetic materials have attracted extensive attention in the field of spintronics. Heterojunctions based on two-dimensional magnetic materials provide important opportunities for the research and development of low-power current-driven spin storage and logic devices;

[0003] At present, current-driven magnetization reversal without magnetic field assistance has been achieved in two-dimensional magnetic material / heavy metal heterostructures at room temperature. However, due to the easy oxidation of the surface of two-dimensional magnetic materials, the interface between two-dimensional magnetic materials and heavy metals is not conducive to the injection of spin current from heavy metals into two-dimensional magnetic materials, resulting in low spin injection efficiency, low current-driven magnetization reversal rate, and difficulty in achieving deterministic reversal at room temperature for heterojunctions, seriously affecting the application of two-dimensional magnetic materials in low-power spin devices;

[0004] In view of the above problems, the inventor proposes a low-temperature annealing method for improving the interfacial spin injection efficiency of two-dimensional magnetic materials to solve the above problems. Summary of the Invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a low-temperature annealing method for improving the interfacial spin injection efficiency of two-dimensional magnetic materials.

[0006] To solve the above technical problems, the present invention adopts the following technical scheme: A low-temperature annealing method for improving the interfacial spin injection efficiency of two-dimensional magnetic materials, comprising the following steps:

[0007] S1. First, obtain two-dimensional magnetic material Fe3GaTe2 with perpendicular magnetic anisotropy, then place Fe3GaTe2 on an oxidized Si substrate, and then use magnetron sputtering to grow heavy metal Pt to construct a Fe3GaTe2 / Pt heterostructure;

[0008] S2. Perform low-temperature ultra-high vacuum annealing treatment on the Fe3GaTe2 / Pt heterostructure to remove excess oxygen ions at the interface and obtain an atomic-level flat interface.

[0009] In S1, the two-dimensional magnetic material Fe3GaTe2 is obtained by mechanical exfoliation.

[0010] In S2, the temperature of the low-temperature ultra-high vacuum annealing treatment is 100 °C.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0012] 1. In the present invention, by optimizing the Fe3GaTe2 / Pt heterojunction interface using ultra-high vacuum annealing, the spin injection efficiency and magnetization reversal rate are effectively improved.

[0013] 2. In the present invention, by adopting an annealing temperature of 100 °C, which is much lower than the temperature in the annealing processes of the prior art, this annealing process has the characteristics of simple operation, easy implementation, low energy consumption, etc., and can be applied in the semiconductor industry.

[0014] 3. In the present invention, in the Fe3GaTe2 / Pt heterostructure treated by low-temperature ultra-high vacuum annealing, the current-driven magnetization reversal rate exceeds 95%, achieving deterministic reversal, which is more than 6 times higher than that of the sample before annealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following-described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a flowchart of a low-temperature annealing method for improving the spin injection efficiency at the interface of two-dimensional magnetic materials according to the present invention.

[0017] Figure 2 It is an optical photograph of Fe3GaTe2(34nm) / Pt(7nm) Hall bar according to the present invention.

[0018] Figure 3 It is the room-temperature anomalous Hall curves of Fe3GaTe2(34nm) / Pt(7nm) Hall bar (a) before annealing and (b) after annealing according to the present invention.

[0019] Figure 4 It is the current-driven magnetization reversal diagram of Fe3GaTe2(34nm) / Pt(7nm) Hall bar before annealing according to the present invention.

[0020] Figure 5 It is the current-driven magnetization reversal diagram of Fe3GaTe2(34nm) / Pt(7nm) Hall bar after annealing according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0022] Embodiment: As Figures 1-5 shown, the present invention provides a low-temperature annealing method for improving the interfacial spin injection efficiency of two-dimensional magnetic materials, including the following steps:

[0023] S1. First, obtain two-dimensional magnetic material Fe3GaTe2 with perpendicular magnetic anisotropy through mechanical exfoliation (using two-dimensional magnetic material Fe3GaTe2 prepared by Shanghai Pumi Precision Instrument Technology Co., Ltd.), then place Fe3GaTe2 on an oxidized Si substrate (using an Si substrate prepared by Hefei Kejing Materials Technology Co., Ltd.), and then use magnetron sputtering to grow heavy metal Pt (using a magnetron sputtering device of Keba Composite Ultra-High Vacuum Deposition System) to construct a Fe3GaTe2 / Pt heterostructure. The spin Hall effect of heavy metal Pt converts the transverse charge current into a longitudinal spin current (using a Pt target prepared by Yanyijin New Materials Co., Ltd.) and injects it downward into perpendicularly magnetized Fe3GaTe2;

[0024] S2. Perform low-temperature ultra-high vacuum annealing treatment on the Fe3GaTe2 / Pt heterostructure. At 100 °C, anneal for 60 min, and the vacuum degree is 10^-9 Torr to remove excess oxygen ions at the interface and obtain an atomically flat interface;

[0025] Since the two-dimensional magnetic material Fe3GaTe2 is exposed to the atmosphere during the preparation process, its surface will be oxidized, resulting in the oxidation of the Fe3GaTe2 / Pt interface in the heterojunction;

[0026] When an in-plane current passes through Fe3GaTe2, the spin Hall effect of heavy metal Pt will convert the transverse charge current into a longitudinal spin current and inject it downward into perpendicularly magnetized Fe3GaTe2, thereby realizing current-driven magnetization reversal at room temperature. However, the oxidized interface in the Fe3GaTe2 / Pt heterostructure will result in a low reversal rate. Through low-temperature ultra-high vacuum annealing treatment, excess oxygen ions at the interface are removed, an atomically flat interface is obtained, the interfacial spin injection efficiency is improved, and thus the room-temperature magnetization reversal rate is significantly increased;

[0027] Obtain the optical micrograph of Fe3GaTe2(34 nm) / Pt(7 nm) Hall bar through an optical microscope, as shown in Figure 2, the room-temperature anomalous Hall curves of Fe3GaTe2(34nm) / Pt(7nm) before and after Hall bar annealing were obtained, as shown in Figure 3 , the flipping rate of current-driven magnetization reversal of Fe3GaTe2(34nm) / Pt(7nm) before Hall bar annealing was 15%, as shown in Figure 4 , the flipping rate of current-driven magnetization reversal of Fe3GaTe2(34nm) / Pt(7nm) after Hall bar annealing was 95%, as shown in Figure 5 , deterministic flipping was achieved, which was more than 6 times higher than that of the sample before annealing, effectively improving the spin injection efficiency and magnetization flipping rate.

[0028] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A low temperature annealing method for improving the interface spin injection efficiency of two-dimensional magnetic materials, characterized in that: The following steps are involved: S1. First, obtain the two-dimensional magnetic material Fe3GaTe2 with perpendicular magnetic anisotropy, then place Fe3GaTe2 on an oxidized Si substrate, and then use magnetron sputtering to grow heavy metal Pt to construct a Fe3GaTe2 / Pt heterostructure; S2. The Fe3GaTe2 / Pt heterostructure is subjected to low-temperature ultra-high vacuum annealing to remove excess oxygen ions at the interface and obtain an atomically flat interface.

2. A low temperature annealing method for improving the interface spin injection efficiency of two-dimensional magnetic materials according to claim 1, characterized in that: In S1, the two-dimensional magnetic material Fe3GaTe2 is obtained by a mechanical exfoliation method.

3. A low temperature annealing method for improving the interface spin injection efficiency of two-dimensional magnetic materials according to claim 1, characterized in that: In S2, the temperature of the low-temperature ultra-high vacuum annealing treatment is 100°C.

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