A material with antiferromagnetic properties and preparation and use thereof

Abstract

The present disclosure provides a material with antiferromagnetic metallicity and preparation and application thereof, and a general formula of the material with antiferromagnetic metallicity is R x A 1‑x BO3, wherein the R is a lanthanide element; the value of x is within 0.01 to 0.30; and the atomic structure of the material is a stacking of octahedral layers observed along the c-axis direction of the crystal structure. The new material with ab-plane controllable antiferromagnetic metal state provided by the present disclosure has higher electrical conductivity and ab-plane controllable antiferromagnetic order; in addition, the material can be converted into ferromagnetic order under high magnetic field, showing controllable antiferromagnetic order under magnetic field.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to, but is not limited to, a material with antiferromagnetic metallicity, and in particular to, but not limited to, a material with antiferromagnetic metallicity and its preparation and application. BACKGROUND

[0002] Magnetic materials in nature can be divided into ferromagnetic (ferrimagnetic) and antiferromagnetic according to whether they contribute to the macroscopic magnetic moment. Due to different conduction mechanisms, ferromagnetic materials generally exhibit metallic behavior, while antiferromagnetic materials generally exhibit insulating behavior. From the perspective of basic research and application, it is of great significance to find ferromagnetic materials with "abnormal" insulating behavior and antiferromagnetic materials with metallic behavior. Currently, there are very few materials confirmed as antiferromagnetic metals, but they all exhibit rich physical properties and application prospects. For example, MnBi2Te4, the magnetic ground state of this material exhibits antiferromagnetism along the c-axis direction, and the antiferromagnetic order can be changed to ferromagnetic order by a magnetic field along the c-axis direction. This material is also the first intrinsic antiferromagnetic topological insulator material, which can realize quantum anomalous Hall effect at a relatively high temperature.

[0003] Existing materials with antiferromagnetic metallicity are extremely rare, and most of them belong to two-dimensional van der Waals materials. Oxides are even rarer, and it is even more rare that the antiferromagnetic order of these materials can be effectively regulated by an external magnetic field. SUMMARY

[0004] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0005] In the embodiments of the present disclosure, a material with antiferromagnetic metallicity is provided, and the general formula of the material is R x A 1-x BO3, wherein the R is a lanthanide element; the value of x is within 0.01 to 0.30;

[0006] The A is selected from the group consisting of group IIA main group elements, such as Ca and Sr, etc., and the B is selected from the group consisting of 3d transition metal elements, such as Fe, Co and Ni, etc.

[0007] When observed along the c-axis direction of the crystal structure, the atomic structure of the material is a stack of octahedral layers (brown iron ore structure).

[0008] In some embodiments provided by the present disclosure, the material is selected from Gd 0.1 Ca 0.9 CoO3, La 0.1 Ca 0.9 CoO3, Nd 0.1 Ca 0.9 CoO3, Sm 0.1 Ca0.9 CoO3, Dy 0.1 Ca 0.9 CoO3, Er 0.1 Ca 0.9 CoO3and Lu 0.1 Ca 0.9 CoO3, etc. La-doped elements. In some embodiments provided by the present disclosure, the anti-ferromagnetic performance of the material is along the ab plane direction of the crystal structure.

[0009] In some embodiments provided by the present disclosure, the method for preparing the material with anti-ferromagnetic property comprises:

[0010] ferrimagnetic semiconductor material R x A 1-x BO 2.5 annealing in an atmosphere containing oxygen radicals;

[0011] the ferrimagnetic semiconductor material R x A 1-x BO 2.5 R in the formula is a lanthanide element, and x is within 0.01 to 0.30; A is selected from the group II A main group elements, and B is selected from the group of 3d transition metal elements.

[0012] In some embodiments provided by the present disclosure, the annealing rate is 1-3 °C / min.

[0013] In some embodiments provided by the present disclosure, the ferrimagnetic semiconductor material R x A 1-x BO 2.5 annealing at 250-300 °C;

[0014] In some embodiments provided by the present disclosure, the ferrimagnetic semiconductor material R x A 1-x BO 2.5 annealing time is 3-7 h.

[0015] In some embodiments provided by the present disclosure, the ferrimagnetic semiconductor material R x A 1-x BO 2.5 the atomic structure of the material is an alternate stacking structure of one layer of B-O tetrahedron and one layer of B-O octahedron along the c-axis direction of the crystal structure (brown iron ore structure).

[0016] In some embodiments provided by the present disclosure, the ferrimagnetic semiconductor material R x A 1-x BO 2.5The material grows on the surface of the substrate in a thin film shape. Annealing itself does not limit the shape and size of the material.

[0017] In some embodiments provided by the present disclosure, the ferrimagnetic semiconductor material R x A 1-x BO 2.5 The thickness of the thin film is 2 nm to 500 nm.

[0018] In some embodiments provided by the present disclosure, the ferrimagnetic semiconductor material R x A 1-x BO 2.5 The preparation method of the ferrimagnetic semiconductor material R

[0019] The R x A 1-x BO 2.5 target material is formed on the surface of the substrate by any one of physical vapor deposition, chemical vapor deposition, electroplating, vacuum thermal evaporation, vacuum electron beam evaporation, direct current sputtering, magnetron sputtering, radio frequency sputtering or pulsed laser deposition. x A 1-x BO 2.5 .

[0020] In some embodiments provided by the present disclosure, the R x A 1-x BO 2.5 The preparation method of the R x A 1-x BO 2.5 target material includes uniformly mixing oxides of R, A and B in a stoichiometric ratio, and then high-temperature sintering to obtain the R x A 1-x BO 2.5 target material.

[0021] In some embodiments provided by the present disclosure, the material of the substrate is any one of (001)-oriented, (110)-oriented and (111)-oriented materials.

[0022] In some embodiments provided by the present disclosure, the substrate is any one or more of YAlO3, SrTiO3, LaAlO3, (LaAlO3) 0.3 -(SrAl 0.5 Ta 0.5 O3) 0.7 and LaSrAlO4.

[0023] In another aspect, the embodiments of the present disclosure provide a magnetic order control method of the material with antiferromagnetic property as described above, and the magnetic order control method includes:

[0024] applying an external magnetic field to the material along the ab plane direction of the atomic structure of the material, the antiferromagnetic order of the material is converted into ferromagnetic order;

[0025] after the external magnetic field is removed, the ferromagnetic order of the material is converted back into antiferromagnetic order.

[0026] The present disclosure provides a material with antiferromagnetic metallicity, which is one of the few oxide materials with controllable in-plane (perpendicular to the film sample surface) antiferromagnetic metal state.

[0027] In another aspect, the present disclosure provides the use of the above-mentioned material with antiferromagnetic metallicity in any one or more of logic devices, memory devices, catalytic materials, electromagnetic wave transmitters, electromagnetic wave receivers, and photoelectric conversion elements.

[0028] The beneficial effects of the present disclosure relative to the prior art include:

[0029] The present disclosure provides a new material with controllable in-plane antiferromagnetic metal state, and provides a new approach to realize the preparation of such materials. The material has high electrical conductivity and controllable antiferromagnetic order in the ab plane, and can be converted into ferromagnetic order under high magnetic field. The antiferromagnetic order in the material is also controllable by magnetic field.

[0030] Other features and advantages of the present disclosure will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present disclosure. Other advantages of the present disclosure can be realized and obtained by the solutions described in the specification. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings are used to provide an understanding of the technical solutions of the present disclosure, and constitute a part of the specification, and together with the embodiments of the present disclosure, are used to explain the technical solutions of the present disclosure, and do not constitute a limitation on the technical solutions of the present disclosure.

[0032] Figure 1 R is La 0.1 Ca 0.9 CoO 2.5 atomic structure of LaAlO3(001) substrate (left) and R 0.1 Ca 0.9 CoO3(right).

[0033] Figure 2 X-ray diffraction pattern (XRD), 2θ / ω scan of Gd 0.1 Ca 0.9 CoO 2.5 and Gd 0.1 Ca 0.9 CoO3film.

[0034] Figure 3 is the curve of magnetization intensity (M) changing with magnetic field (H) and temperature (T). Figure 3 The corresponding test temperature in (a) is 30K, and the test in (b) is the test result of the heating process after the temperature is dropped from room temperature to 10K under 1kOe magnetic field.

[0035] Figure 4 For Gd 0.1 Ca 0.9 The resistivity curve of CoO3 film changes with temperature.

[0036] Figure 5 R 0.1 Ca 0.9 Curve of the in-plane magnetization intensity (M) of CoO3 film changing with the magnetic field (H), corresponding to the test temperature of 50K, where R = La, Nd, Sm, Gd, Dy, Er, Lu. DETAILED DESCRIPTION

[0037] To make the purpose, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure are described in detail below. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other in any manner.

[0038] The R used in the examples and comparative examples of the present disclosure 0.1 A 0.9 BO 2.5 The target material preparation method includes:

[0039] The oxides of R, A and B are divided into the following order: x A 1-x BO 2.5 The mixed powders were uniformly mixed according to the stoichiometric ratio, pressed into a certain shape and size, sintered at 1200°C in an atmospheric environment for 12 hours, and then annealed at a rate of 200°C / h to obtain the R x A 1-x BO 2.5 target material.

[0040] Example 1:

[0041] A thin film of ferrimagnetic semiconductor material Gd was prepared on the LaAlO3 (001) substrate by means of a pulsed laser deposition system. 0.1 Ca 0.9 CoO 2.5 , Gd 0.1 Ca 0.9 CoO 2.5 The thickness is 2nm to 500nm. The atomic structure of the material is as follows Figure 1 As shown in the left figure, the crystal structure is observed in the c-axis direction, and the grown Gd0.1 Ca 0.9 CoO 2.5 It has a structure with alternating stacking of one layer of Co-O tetrahedra and one layer of Co-O octahedra, which exhibits ferrimagnetic semiconductor behavior.

[0042] Gd 0.1 Ca 0.9 CoO 2.5 Annealing at 300°C in an atmosphere containing oxygen free radicals at 1°C / min to 3°C / min for 3h to 7h yields Gd 0.1 Ca 0.9 CoO3, atomic structure is as follows Figure 1 As shown in the middle right figure, when observed along the c-axis direction of the crystal structure, all octahedral layers are stacked, among which 10% of the Ca ions are replaced by Gd ions, showing preferential site doping. This material has antiferromagnetic metallic behavior that can be controlled by an external magnetic field along the ab plane direction of the crystal structure.

[0043] Example 2:

[0044] The thin film ferrimagnetic semiconductor material La prepared on the LaAlO3 (001) substrate using the process method of Example 1 0.1 Ca 0.9 CoO 2.5 (Compared to Gd in Example 1 0.1 Ca 0.9 CoO 2.5 have the same crystal structure), La 0.1 Ca 0.9 CoO 2.5 Annealing at 300℃ in an atmosphere containing oxygen radicals yields La 0.1 Ca 0.9 CoO3 (with Gd prepared in Example 1 0.1 Ca 0.9 CoO3 has the same crystal structure) and exhibits antiferromagnetic metallic behavior that can be controlled by an external magnetic field along the ab plane direction of the crystal structure.

[0045] Example 3:

[0046] The thin film ferrimagnetic semiconductor material Nd prepared on the LaAlO3 (001) substrate using the process method of Example 1 0.1 Ca 0.9 CoO 2.5 (Compared to Gd in Example 1 0.1 Ca 0.9 CoO 2.5 have the same crystal structure), Nd 0.1 Ca 0.9 CoO 2.5annealing at 300°C in an atmosphere containing oxygen radicals, Sm 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd 2.5 Ca 0.1 CoO3( having the same crystal structure as Gd 0.9 Ca 2.5 CoO3( having the same crystal structure as Gd 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd 2.5 Ca 0.1 CoO3( having the same crystal structure as Gd 0.9 Ca 0.1 CoO3( having the same crystal structure as Gd 0.9 Ca 0.1 CoO3( having the same crystal structure as Gd 0.9 Ca 2.5 CoO3( having the same crystal structure as Gd 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd 2.5 Ca 0.1 CoO3( having the same crystal structure as Gd 0.9 Ca 2.5 CoO3( having the same crystal structure as Gd 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd

[0047] Example 4:

[0048] Example 1 on the LaAlO3(001) substrate using the process method of Example 1 0.9 Ca 0.1 CoO3( having the same crystal structure as Gd 0.9 Ca 0.1 CoO3( having the same crystal structure as Gd 0.9 Ca 2.5 CoO3( having the same crystal structure as Gd 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd 2.5 Ca 0.1 CoO3( having the same crystal structure as Gd 0.9 Ca 2.5 CoO3( having the same crystal structure as Gd 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd

[0049] Example 5:

[0050] Example 1 on the LaAlO3(001) substrate using the process method of Example 1 0.9 Ca 2.5 CoO3( having the same crystal structure as Gd 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd 0.1 Ca 0.9 CoO3( having the same crystal structure as Gd

[0051] Example 6:

[0052] A thin film-like ferrimagnetic semiconductor material Er 0.1 Ca 0.9 CoO 2.5 (with the same crystal structure as Gd 0.1 Ca 0.9 CoO 2.5 with the same crystal structure as Gd 0.1 Ca 0.9 CoO 2.5 annealed in an atmosphere containing oxygen radicals at 300°C to obtain Er 0.1 Ca 0.9 CoO3(with the same crystal structure as Gd 0.1 Ca 0.9 CoO3(with the same crystal structure as Gd

[0053] Example 7:

[0054] A thin film-like ferrimagnetic semiconductor material Lu 0.1 Ca 0.9 CoO 2.5 (with the same crystal structure as Gd 0.1 Ca 0.9 CoO 2.5 with the same crystal structure as Gd 0.1 Ca 0.9 CoO 2.5 annealed in an atmosphere containing oxygen radicals at 300°C to obtain Lu 0.1 Ca 0.9 CoO3(with the same crystal structure as Gd 0.1 Ca 0.9 CoO3(with the same crystal structure as Gd

[0055] In summary, through the characterization of the above-mentioned various La-doped samples, it can be concluded that all the specific proportion La-doped calcium cobalt oxide materials have the ab-plane direction external magnetic field controllable antiferromagnetic metal behavior. The results of Examples 1 to 7 are summarized in Figure 5 .

[0056] Comparative Example 1:

[0057] The difference between this comparative example and Example 1 is that the atmosphere containing oxygen radicals in Example 1 is replaced by pure oxygen. Other processes are exactly the same as Example 1.

[0058] In pure oxygen, R0.1 Ca 0.9 CoO3 (R = La series element) material does not have the antiferromagnetic metal property that can be controlled by an external magnetic field along the ab plane direction.

[0059] In addition, an R ratio between ~0.01 and ~0.30 can achieve antiferromagnetic metallic properties that are controllable in the external magnetic field along the ab plane direction, corresponding to a Ca ratio of ~0.99 to ~0.70.

[0060] Figure 2 、 Figure 3 and Figure 4 The specific experimental data are all taken from the Gd prepared in Example 1 0.1 Ca 0.9 CoO3 thin films and other La-based doping materials with the same proportion have similar properties.

[0061] By using the 2θ / ω scanning of X-ray diffractometer (XRD), the information of the out-of-plane lattice period of the whole sample can be obtained. Figure 2 As shown, the R grown on LaAlO3(001) substrate 0.1 Ca 0.9 CoO 2.5 (R=La series element Gd) film, and R after ozone annealing at 300℃ for three hours 0.1 Ca 0.9 CoO3 (R = La series element Gd) thin film. According to the Bragg diffraction formula, the out-of-plane lattice constant changes from 1.513nm to 0.371nm, and the out-of-plane period changes from 4 Co-O layers to 1 Co-O octahedral layer. This indicates that the entire sample has been completely oxidized, and a uniform and high-quality R 0.1 Ca 0.9 CoO3 (R = La-based element Gd) thin film.

[0062] The R 0.1 Ca 0.9 The macroscopic magnetic properties of CoO3 (R = La series element Gd) thin films were measured, and the experimental results are as follows. Figure 3 As shown in Figure 2, the material has obvious antiferromagnetic performance at low temperature and low field. Figure 3(a) is the hysteresis loop of the magnetization intensity (M) at 30K temperature as the magnetic field (H) changes. The direction of the magnetic field is along the ab plane (i.e., in-plane) direction of the atomic structure of the material. Under low magnetic field, the magnetization intensity increases slowly and linearly with the magnetic field. As the magnetic field increases, after exceeding the critical magnetic field, the magnetization intensity increases sharply and eventually changes to a ferromagnetic state. This result shows that through a certain magnetic field (about 45kOe at this temperature), the original antiferromagnetic ground state of the material can be artificially modulated into a ferromagnetic excited state. This controllable magnetic field will play a great role in the field of self-selected electronics. The antiferromagnetic transition temperature of this material is as follows: Figure 3 As shown in (b), it is about 55K.

[0063] The R 0.1 Ca 0.9 The resistivity of CoO3 (R = La series element Gd) film is measured, such as Figure 4 As shown, the R 0.1 Ca 0.9 The resistivity of CoO3 (R = La-based element Gd) decreases significantly as the temperature decreases, and the absolute value is very small. Its resistivity can reach below 500 μΩ·cm, which clearly shows metallic properties.

[0064] Antiferromagnetic metals have gained significant application in spintronics due to their superior performance. Compared to ferromagnetic materials, antiferromagnetic metals exhibit strong resistance to external magnetic fields, generate no stray fields, exhibit faster response, and produce greater magnetotransport effects. These advantages in energy efficiency and size have garnered unprecedented attention in highly integrated magnetic devices such as disk read heads and magnetic random access memory (MRAM). Furthermore, antiferromagnetic metals are gradually replacing ferromagnetic materials in next-generation electronic spintronic devices being studied in laboratories. Numerous spin logic devices based on antiferromagnetic properties have been proposed and tested, and it is expected that antiferromagnetic devices will see even greater industrial applications in the near future.

Claims

1. A material having antiferromagnetic metallic properties, characterized in that: The general formula of the material is R x A 1-x BO3, wherein the R is a lanthanide element; the value of x is within the range of 0.01 to 0.30; The A is selected from the elements of the IIA main group, and the B is selected from 3d transition metal elements; Observing along the c-axis direction of the crystal structure, the atomic structure of the material is a stacking of octahedral layers.

2. The material having antiferromagnetic metallic properties according to claim 1, characterized in that: The material is selected from Gd 0.1 Ca 0.9 CoO3、La 0.1 Ca 0.9 CoO3、Nd 0.1 Ca 0.9 CoO3、Sm 0.1 Ca 0.9 CoO3、Dy 0.1 Ca 0.9 CoO3、Er 0.1 Ca 0.9 CoO3 and Lu 0.1 Ca 0.9 Any one or more of CoO3.

3. The method for preparing the material having antiferromagnetic metallic properties according to claim 1, characterized in that: The preparation method comprises: Ferrimagnetic semiconductor materials R x A 1-x BO 2.5 Annealing in an atmosphere containing oxygen free radicals; The ferrimagnetic semiconductor material R x A 1-x BO 2.5 in R is a lanthanide element, the value of x is within the range of 0.01 to 0.30; said A is selected from the elements of the IIA main group, and said B is selected from 3d transition metal elements; The ferrimagnetic semiconductor material R x A 1-x BO 2.5 The atomic structure of the quartz crystal is an alternating stacking structure of one layer of BO tetrahedron and one layer of BO octahedron along the c-axis direction of the crystal structure.

4. The preparation method according to claim 3, characterized in that The annealing rate is 1°C / min to 3°C / min.

5. The preparation method according to claim 4, characterized in that The ferrimagnetic semiconductor material R x A 1-x BO 2.5 Anneal at 250°C to 300°C.

6. The preparation method according to claim 4, characterized in that The ferrimagnetic semiconductor material R x A 1-x BO 2.5 The annealing time is 3 h to 7 h.

7. The preparation method according to any one of claims 3 to 6, characterized in that The ferrimagnetic semiconductor material R x A 1-x BO 2.5 It grows on the substrate surface in the form of a thin film.

8. The preparation method according to claim 7, characterized in that The ferrimagnetic semiconductor material R x A 1-x BO 2.5 The thickness of the film ranges from 2 nm to 500 nm.

9. The preparation method according to any one of claims 3 to 6, characterized in that The ferrimagnetic semiconductor material R x A 1-x BO 2.5 The preparation method comprises: use R x A 1-x BO 2.5 The target material is formed on the substrate surface by any of the following methods: physical vapor deposition, chemical vapor deposition, electroplating, vacuum thermal evaporation, vacuum electron beam evaporation, DC sputtering, magnetron sputtering, radio frequency sputtering or pulsed laser deposition. R x A 1-x BO 2.5 .

10. The preparation method according to claim 9, characterized in that described R x A 1-x BO 2.5 The target material preparation method includes: Will R The oxides of A, B and B are R x A 1-x BO 2.5 The mixture is uniformly mixed according to the stoichiometric ratio and then sintered at high temperature to obtain the R x A 1-x BO 2.5 target material.

11. The preparation method according to claim 9, characterized in that The material of the substrate is selected from materials with any one of (001) orientation, (110) orientation and (111) orientation.

12. The preparation method according to claim 11, characterized in that The substrate is selected from YAlO3, SrTiO3, LaAlO3, (LaAlO3) 0.3 -(SrAl 0.5 Ta 0.5 O3) 0.7 and any one or more of LaSrAlO4.

13. The method for controlling the magnetic order of a material having antiferromagnetic metallic properties according to claim 1 or 2, characterized in that: The magnetic order control method comprises: applying an external magnetic field to the material along the ab plane direction of the atomic structure of the material to convert the antiferromagnetic order of the material into a ferromagnetic order; After the external magnetic field is removed, the ferromagnetic order of the material transforms back into an antiferromagnetic order.

14. Use of the material having antiferromagnetic metallic properties according to claim 1 or 2 in any one or more of logic devices, memory devices, catalytic materials, electromagnetic wave transmitters, electromagnetic wave receivers and photoelectric conversion elements.

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