阅读说明：本技术 一种CuFeSb薄膜制备方法 (Preparation method of CuFeSb film ) 是由 李卓君 牟刚 徐丽璇 季秋骋 宋叶凯 彭炜 于 2019-07-29 设计创作，主要内容包括：本发明公开了一种CuFeSb薄膜制备方法,该方法包括以下步骤：S1.制备CuFeSb多晶靶材；S2.提供一立方或四方晶型单晶衬底；S3.对所述单晶衬底进行清洗处理；S4.对清洗后的所述单晶衬底进行退火处理；S5.烧蚀所述CuFeSb多晶靶材,在所述单晶衬底表面生长CuFeSb薄膜。本发明利用脉冲激光沉积技术,通过高真空设备、准分子激光器硬件、多晶靶材的合成、衬底的选取、衬底的处理、薄膜合成参数的稳定控制,可以制备出面外高度取向的CuFeSb薄膜,有助于推动CuFeSb物性的研究,且该薄膜相比多晶体材料拥有很大的优势,拓展了CuFeSb物性调控的手段,对该材料在基础研究和磁性材料应用上有极大价值。(The invention discloses a preparation method of a CuFeSb film, which comprises the following steps: s1, preparing a CuFeSb polycrystalline target material; s2, providing a cubic or tetragonal crystal type single crystal substrate; s3, cleaning the single crystal substrate; s4, annealing the cleaned single crystal substrate; s5, ablating the CuFeSb polycrystalline target material, and growing a CuFeSb film on the surface of the single crystal substrate. The method utilizes the pulse laser deposition technology, and can prepare the CuFeSb film with high orientation out of the surface through high vacuum equipment, excimer laser hardware, synthesis of polycrystalline target materials, selection of the substrate, treatment of the substrate and stable control of film synthesis parameters, thereby being beneficial to promoting the research of CuFeSb physical properties.)

1. A preparation method of a CuFeSb film is characterized by comprising the following steps:

s1, preparing a CuFeSb polycrystalline target material;

s2, providing a cubic or tetragonal crystal type single crystal substrate;

s3, cleaning the single crystal substrate;

s4, annealing the cleaned single crystal substrate;

s5, ablating the CuFeSb polycrystalline target material, and growing a CuFeSb film on the surface of the single crystal substrate.

2. The method for preparing a CuFeSb film according to claim 1, wherein the CuFeSb polycrystalline target material in the step S1 is prepared by sintering by a solid phase method.

3. The method for preparing a CuFeSb thin film according to claim 2, wherein the step S1 comprises the following steps:

s11, weighing raw materials: weighing the mixture according to a molar ratio of 1: 1: 1 of Cu powder, Fe powder and Sb powder;

s12, primary grinding: grinding the weighed raw materials in an inert atmosphere glove box for 20-60min to form powder with the fineness of 100-200 meshes;

s13, vacuum sealing, namely sealing the ground powder in a vacuum degree of not less than 5 × 10^-4Pa quartz tube;

s14, first sintering: putting the quartz tube filled with the powder into a box-type muffle furnace, heating to 700-800 ℃, preserving the heat for 12-36h at the temperature, and then cooling to room temperature to form a lump material;

s15, secondary grinding: grinding the block material in an inert atmosphere glove box for 20-60min to form powder with the fineness of 100-200 meshes;

s16, press forming: putting the ground powder into a die, and pressing into a wafer with the diameter of 10-14mm and the thickness of 2-3mm under the pressure of 5-7 MPa;

s17, vacuum sealing again, namely sealing the wafer in a vacuum degree of not less than 5 × 10^-4Pa quartz tube;

s18, secondary sintering: and (3) putting the quartz tube with the wafer into a box-type muffle furnace, heating to 700-800 ℃, preserving the heat for 6-24h at the temperature, and then cooling to room temperature.

4. The method for preparing CuFeSb film according to claim 1, wherein the single crystal substrate of cubic or tetragonal type in step S2 is SrTiO₃、LaAlO₃And MgO.

5. The method for preparing a CuFeSb thin film according to claim 1, wherein the single crystal substrate in the step S3 is cleaned by an organic solvent.

6. The method for preparing a CuFeSb thin film according to claim 5, wherein the step S3 comprises the following steps:

s31, sequentially putting the single crystal substrate into acetone, alcohol and isopropanol for ultrasonic cleaning for 1-60 min;

s32, blowing the cleaned single crystal substrate by using inert gas, wherein the inert gas is nitrogen or argon.

7. The method for preparing the CuFeSb thin film according to claim 1, wherein the annealing treatment in the step S4 is performed in a pulsed laser deposition system.

8. The method for preparing a CuFeSb thin film according to claim 7, wherein the step S4 comprises the following steps:

and (3) introducing the single crystal substrate into a pulse laser deposition vacuum chamber, setting the temperature to be 500-.

9. The method for preparing a CuFeSb film according to claim 1, wherein the step S5 of ablating the CuFeSb polycrystalline target material is performed in a pulsed laser deposition system.

10. The method for preparing CuFeSb film according to claim 9, wherein the laser in the pulsed laser deposition system is of wavelength248nm KrF excimer laser with laser energy of 120-150mJ and growth chamber back vacuum degree superior to 5 × 10^-5Pa, the substrate temperature is 300-500 ℃.

Technical Field

The invention relates to the field of material synthesis, in particular to a preparation method of a CuFeSb film.

Background

Iron-based superconduction is the second major high-temperature superconduction family discovered in 2008 after copper-based high-temperature superconduction, and the discovery breaks through the thoughts that iron elements are generally recognized to be unfavorable to form superconduction. The crystal structure, the magnetic structure and the electronic phase diagram of the iron-based superconducting system and the copper-based superconducting are very similar, particularly the structure of the iron-based superconductor is similar to the copper-oxygen plane of high-temperature superconducting, and the superconductivity occurs on the iron-based plane and belongs to a two-dimensional superconducting material. Therefore, the research on iron-based superconductivity helps to promote the solution process of the high-temperature superconductivity mechanism.

Iron-based superconducting materials are mainly classified into "1111" systems according to the characteristics of crystal structures, and the members include LnOFePn (Ln ═ La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Y; Pn ═ P, As), DvFeAsF (Dv ═ Ca, Sr), and the like; members of the "122" system including AFe₂As₂(a ═ Ba, Sr, K, Cs, Ca, Eu), and the like; members of the "111" system include AFeAs (a ═ Li, Na), and the like; members of the "11" system include FeSe (Te), and the like. At present, the maximum superconducting transition temperature of the bulk material is 56K, while the superconducting transition temperature of the single-layer FeSe film exceeds even 9K of the bulk material to 65K, so that the highest record of the iron-based superconducting transition temperature is kept. A large number of theory and experimental results show that electro-acoustic interaction and charge transfer from a substrate are important factors for enhancing the superconductivity of the single-layer FeSe film, and a new thought and a new way are provided for people to search for materials with higher superconducting transition temperature, wherein on one hand, a material system similar to iron-based superconductivity and having a crystal structure is searched, and on the other hand, the material system is providedThe search for low dimensional systems including high temperature superconductivity that may occur in thin film materials is pursued.

CuFeSb is a layered ferromagnetic metal material discovered in recent two years, and the ferromagnetic Curie temperature is 375K. It has a crystal structure similar to that of AFeAs (A ═ Li, Na) of Fe-based superconducting '111' system. Has a tetragonal crystal structure at room temperature, and each cell contains one (Fe)₂Sb₂)^4-Layer, two Cu atoms of different planes will be (Fe)₂Sb₂)^2-The layers are spaced apart. Theoretical calculations indicate that a greater height (Z) of the Sb layer from the plane of the Fe atoms, relative to the height (ZAs) of the As layer from the plane of the Fe atoms in an iron-based superconductor_Sb) Is responsible for the CuFeSb ferromagnetic metallic state, rather than the iron-based superconducting antiferromagnetic ground state. The research on the physical properties and the regulation and control of CuFeSb is helpful for understanding the superconducting mechanism of the iron-based superconducting material.

At present, physical property and regulation research on CuFeSb is mainly carried out on a polycrystalline sample, chemical element doping on the polycrystalline sample is the most main regulation and control means, the regulation and control means is single, and an obvious regulation and control effect is not obtained for a while. In experiments, multidimensional external field regulation cannot be performed on a polycrystalline sample, for example, an electric field effect is introduced to a thin film sample by adding a gate voltage while introducing substrate stress modulation thin film physical properties. Therefore, a method for preparing a CuFeSb thin film material, which can overcome the above defects, is urgently sought and developed.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a CuFeSb film preparation method, which utilizes a pulse laser deposition technology, and can prepare the CuFeSb film with high out-of-plane orientation through high vacuum equipment, excimer laser hardware, polycrystalline target synthesis, substrate selection, substrate treatment and stable control of film synthesis parameters, thereby being beneficial to promoting the research on the physical properties of the CuFeSb, having great advantages compared with polycrystalline materials, and expanding the means for regulating and controlling the physical properties of the CuFeSb.

The invention is realized by the following technical scheme:

the invention discloses a preparation method of a CuFeSb film, which comprises the following steps:

s1, preparing a CuFeSb polycrystalline target material;

s2, providing a cubic or tetragonal crystal type single crystal substrate;

s3, cleaning the single crystal substrate;

s4, annealing the cleaned single crystal substrate;

s5, ablating the CuFeSb polycrystalline target material, and growing a CuFeSb film on the surface of the single crystal substrate.

Preferably, the CuFeSb polycrystalline target in step S1 is prepared by sintering by a solid phase method.

Preferably, the step S1 includes the steps of:

s11, weighing raw materials: weighing the mixture according to a molar ratio of 1: 1: 1 of Cu powder, Fe powder and Sb powder;

s12, primary grinding: grinding the weighed raw materials in an inert atmosphere glove box for 20-60min to form powder with the fineness of 100-200 meshes;

s13, vacuum sealing, namely sealing the ground powder in a vacuum degree of not less than 5 × 10^-4Pa quartz tube;

s14, first sintering: putting the quartz tube filled with the powder into a box-type muffle furnace, heating to 700-800 ℃, preserving the heat for 12-36h at the temperature, and then cooling to room temperature to form a lump material;

s15, secondary grinding: grinding the block material in an inert atmosphere glove box for 20-60min to form powder with the fineness of 100-200 meshes;

s16, press forming: putting the ground powder into a die, and pressing into a wafer with the diameter of 10-14mm and the thickness of 2-3mm under the pressure of 5-7 MPa;

s17, vacuum sealing again, namely sealing the wafer in a vacuum degree of not less than 5 × 10^-4Pa quartz tube;

s18, secondary sintering: and (3) putting the quartz tube with the wafer into a box-type muffle furnace, heating to 700-800 ℃, preserving the heat for 6-24h at the temperature, and then cooling to room temperature.

Preferably, the cubic or tetragonal single crystal substrate in the step S2 is selected from SrTiO₃、LaAlO₃And MgO.

Preferably, the single crystal substrate in step S3 is subjected to a cleaning process using an organic solvent.

Preferably, the step S3 includes the steps of:

s31, sequentially putting the single crystal substrate into acetone, alcohol and isopropanol for ultrasonic cleaning for 1-60 min;

s32, blowing the cleaned single crystal substrate by using inert gas, wherein the inert gas is nitrogen or argon.

Preferably, the annealing process in step S4 is performed in a pulsed laser deposition system.

Preferably, the step S4 includes the steps of:

and (3) introducing the single crystal substrate into a pulse laser deposition vacuum chamber, setting the temperature to be 500-.

Preferably, the ablating the CuFeSb polycrystalline target in step S5 is performed in a pulsed laser deposition system.

Preferably, the laser in the pulsed laser deposition system is a KrF excimer laser with the wavelength of 248nm, the laser energy is 120-150mJ, and the vacuum degree of the back bottom of the growth chamber is better than 5 × 10^-5Pa, the substrate temperature is 300-500 ℃.

The preparation method of the CuFeSb film provided by the invention has the following beneficial effects:

the method utilizes the pulse laser deposition technology, and can prepare the CuFeSb film with high orientation out of the surface through high vacuum equipment, excimer laser hardware, synthesis of polycrystalline target materials, selection of the substrate, treatment of the substrate and stable control of film synthesis parameters, thereby being beneficial to promoting the research of CuFeSb physical properties.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a flow chart of a method for preparing a CuFeSb film according to an embodiment of the present invention;

FIG. 2 is a flowchart of a method for preparing a CuFeSb polycrystalline target material according to an embodiment of the present invention;

FIG. 3 is a flow chart of a method for cleaning a single crystal substrate according to an embodiment of the present invention;

FIG. 4 shows SrTiO 2 at a temperature of too low a substrate temperature (300 ℃ C.) according to an embodiment of the present invention₃An out-of-plane XRD (X-ray diffraction) spectrum of the CuFeSb film growing on the substrate;

FIG. 5 shows SrTiO 2 at a high substrate temperature (500 ℃ C.) according to an embodiment of the present invention₃An out-of-plane XRD (X-ray diffraction) spectrum of the CuFeSb film growing on the substrate;

FIG. 6 shows SrTiO 2 with a relatively high substrate temperature (400 deg.C) according to an embodiment of the present invention₃An out-of-plane XRD (X-ray diffraction) spectrum of the CuFeSb film growing on the substrate;

FIG. 7 shows SrTiO at a relatively high substrate temperature according to an embodiment of the present invention₃A 100 nm-thick CuFeSb film resistor-temperature curve is grown on the substrate;

FIG. 8 shows SrTiO at an optimized substrate temperature according to an embodiment of the present invention₃The magnetization intensity-temperature curve of zero field cooling and field cooling of the CuFeSb film with the thickness of 100nm grown on the substrate.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention.