CN112479710B

CN112479710B - Nickel-based target material and preparation method and application thereof

Info

Publication number: CN112479710B
Application number: CN202011275834.5A
Authority: CN
Inventors: 裴宇娟; 曹彦伟; 张如意; 彭邵勤; 宋洋
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS
Priority date: 2020-11-16
Filing date: 2020-11-16
Publication date: 2023-01-03
Anticipated expiration: 2040-11-16
Also published as: CN112479710A

Abstract

The invention relates to the field of ceramic targets, in particular to a nickel-based target and a preparation method and application thereof. Through the production process of ball milling, presintering, secondary ball milling, granulation, blank making, glue discharging, programmed heating and sintering and programmed cooling, the Nd with pure components, uniform element and density distribution and good mechanical strength, hardness and compactness is prepared _1‑x A _x NiO ₃ The ceramic target is subjected to magnetron sputtering growth to obtain Nd _1‑x A _x NiO ₃ A thin film having good crystallinity and high quality single crystal epitaxial properties; in addition, the invention also provides an Nd _1‑x A _x NiO ₂ A thin film having excellent superconducting characteristics and electric transport properties.

Description

Nickel-based target material and preparation method and application thereof

Technical Field

The invention relates to the field of ceramic targets, in particular to a nickel-based target and a preparation method and application thereof.

Background

The superconducting material has the characteristics of zero resistance and magnetic line repulsion at a temperature lower than a certain temperature, and is widely applied to the aspects of precision detection elements, energy storage, computers and the like. Superconducting materials have been discovered for over 100 years, copper-based, iron-based, etc. superconducting materials have been discovered in succession, however, until 2019, nickel-based superconduction has not been realized.

Nd _1-x A _x NiO ₃ Nd obtained after reduction (A = Ca or Sr or Ba) _1-x A _x NiO ₂ Can be used for preparing the nickel-based superconducting film, and in addition, has the electrical transport property of metal-insulation phase transition. However, nd in the conventional ceramic target material preparation method _1-x A _x NiO ₃ The preparation method of the ceramic target is little involved in hunting, so that the high-quality Nd _1-x A _x NiO ₃ The preparation of the target material becomes a technical problem which needs to be solved urgently.

Disclosure of Invention

Based on this, it is necessary to provide a high quality Nd _1-x A _x NiO ₃ (A = Ca or Sr or Ba) target material and a preparation method and application thereof.

In one aspect, the invention provides a preparation method of a nickel-based target material, wherein the nickel-based target material comprises Nd _1-x A _x NiO ₃ (A = Ca or Sr or Ba,0 < x < 1) comprising the steps of:

s1, performing first ball milling on neodymium oxide, alkaline earth carbonate and nickel oxide which are used as raw materials, wherein the alkaline earth carbonate is calcium carbonate or strontium carbonate or barium carbonate, and preparing a first intermediate;

s2, presintering the first intermediate at 1150-1250 ℃ for 7-9 h to prepare a second intermediate;

s3, performing secondary ball milling on the second intermediate, and then performing granulation to prepare a third intermediate;

s4, preparing the third intermediate into a target green body, and performing glue discharging treatment to prepare a fourth intermediate;

s5, heating the fourth intermediate to a sintering temperature through a program, sintering, and then cooling to room temperature through the program; the sintering temperature is 1200-1300 ℃, and the sintering time is 2-4 h; the programmed temperature rise comprises: firstly, heating the green body to 850-950 ℃ at the speed of 5-10 ℃/min, keeping the temperature for 0.8-1.2 h, and then heating to the sintering temperature at the heating rate of 2-4 ℃/min; the programmed cooling comprises: at the sintering temperature, the temperature is reduced to 850-950 ℃ at the cooling rate of 2-4 ℃/min, and then the temperature is reduced to the room temperature.

In one embodiment, the ratio of the amounts of the neodymium oxide, the alkaline earth carbonate and the nickel oxide in S1 is as follows: x is 1: 1.

In one embodiment, the first ball milling and/or the second ball milling is wet ball milling, the solvent is at least one selected from absolute ethyl alcohol and deionized water, the milling medium is at least one selected from zirconia and alumina, and the diameter of the milling medium is 0.5mm to 2mm.

In one embodiment, the raw material or the second intermediate is the solvent, the grinding media = (0.8-1.2), the grinding media (0.8-1.2) and the grinding media (1.8-2.2) in parts by mass.

In one embodiment, the binder used for the granulation in S3 is at least one of polyvinyl alcohol solutions.

In one embodiment, the amount of the binder is 1-5% of the mass of the raw materials.

In one embodiment, the particle size of the third intermediate in S3 is 60-140 meshes.

In one embodiment, in S4, the target green compact is obtained by pressure forming the third intermediate, where the pressure is 20MPa to 40MPa, and the pressing time is 10min to 14min.

In one embodiment, the temperature of the glue discharging treatment in S4 is 400-600 ℃, and the time is 2-4 h.

The Nd with pure components, uniform distribution of elements and density, good mechanical strength, hardness and compactness is prepared by the production process of ball milling, pre-sintering, secondary ball milling, granulation, blank making, glue discharging, programmed heating and sintering and programmed cooling _1-x A _x NiO ₃ A ceramic target material. Ball milling is carried out before solid phase reaction, so that the raw materials can be mixed more uniformly; the proper pre-sintering temperature and time can ensure that the decomposition of the carbonate is more thorough when the solid phase reaction occurs, other impurity phases are not generated, and simultaneously, crystal grains with proper size can be obtained, thereby avoiding the influence of overlarge crystal grains and even ceramic bonding on secondary ball milling; the ball milling is carried out again before the blank making, the grain diameter of the ceramic material obtained by the solid phase reaction is smaller and the distribution is more uniform, and the ceramic material with poor fluidity caused by smaller grain diameter after the ball milling can have better fluidity through granulation, so that a high-quality green blank is prepared; the binder removal treatment improves the sintering quality of green bodies and avoids the deformation of the green bodiesCracking; the programmed heating is adopted, so that the thermal stress in the sintering process is reduced, and the target material density is uniformly distributed; the proper sintering temperature and time are set, so that the ceramic target material obtained by sintering has good mechanical strength, hardness and compactness.

In another aspect of the invention, the Nd prepared by the preparation method is provided _1-x A _x NiO ₃ (A = Ca or Sr or Ba,0 < x < 1) target.

In another aspect of the invention, nd prepared from the target material prepared by the preparation method is provided _1-x A _x NiO ₃ (A = Ca or Sr or Ba,0 < x < 1).

In another aspect of the invention, an Nd is also provided _1-x A _x NiO ₂ Superconducting thin film, nd made by the foregoing _1-x A _x NiO ₃ (A = Ca or Sr or Ba,0 < x < 1) film reduction.

Drawings

FIG. 1 is an electron microscope scanning image of a nickel-based ceramic target; wherein (a) represents an SEM topography of the nickel-based ceramic target, (b) represents an O K alpha 1Mapping diagram of the nickel-based ceramic target, and (c) represents an Ni K alpha 1Mapping diagram of the nickel-based ceramic target; (d) shows a Mapping diagram of the nickel-based ceramic target material Sr K alpha 1; (e) shows a drawing of a nickel-based ceramic target Nd L alpha 1 Mapping.

FIG. 2 shows Nd _0.8 Sr _0.2 NiO ₃ A schematic view of diffraction peak and rocking curve of (002) crystal face of the film, wherein (a) represents Nd _0.8 Sr _0.2 NiO ₃ (002) Crystal face diffraction Peak of film, (b) represents Nd _0.8 Sr _0.2 NiO ₃ Rocking curve of the film.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise. In the description of the present invention, "a plurality" means at least one, e.g., one, two, etc., unless specifically limited otherwise.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The invention provides an Nd _1-x A _x NiO ₃ The preparation method of the (A = Ca or Sr or Ba,0 < x < 1) target material comprises the following steps:

s1, performing primary ball milling on neodymium oxide, alkaline earth carbonate and nickel oxide serving as raw materials, wherein the alkaline earth carbonate is calcium carbonate or strontium carbonate or barium carbonate to prepare a first intermediate;

s4, preparing the third intermediate into a target green body and carrying out glue discharging treatment to prepare a fourth intermediate;

s5, heating the fourth intermediate to a sintering temperature through a program, sintering, and then cooling to room temperature through the program; the sintering temperature is 1200-1300 ℃, and the sintering time is 2-4 h; the programmed temperature rise includes: firstly, heating the green body to 850-950 ℃ at the speed of 5-10 ℃/min, keeping the temperature for 0.8-1.2 h, and then heating to the sintering temperature at the heating rate of 2-4 ℃/min; the programmed cooling comprises the following steps: at the sintering temperature, the temperature is reduced to 850-950 ℃ at the cooling rate of 2-4 ℃/min, and then the temperature is reduced to the room temperature.

The raw materials can be uniformly mixed by the first ball milling, so that the subsequent solid-phase reaction can better occur; pre-sintering, namely a solid-phase reaction process, and is used for synthesizing a ceramic material containing target components; the ceramic material obtained by the solid-phase reaction has small and uniform particle size, so that the ceramic material obtained by the solid-phase reaction needs to be subjected to secondary ball milling to further reduce the particle size and improve the uniformity, and the ceramic material is prepared for granulation; because the binder is used in the granulation process, the prepared target green compact needs to be subjected to glue removal treatment before sintering; the purpose of sintering is to enable crystal grains to be fused and bonded under the action of high temperature, so that the finally prepared target has certain mechanical strength and hardness, and the density is improved; the reasonable programmed temperature rise and temperature fall setting can reduce the thermal stress in the sintering process, so that crystal grains can be gradually fused and bonded in the sintering process, the internal pores of the target material are reduced, and the mechanical strength and hardness of the finally prepared ceramic target material are further improved; meanwhile, the temperature is kept at 850-950 ℃ for 0.8-1.2 h, which is beneficial to discharging residual air, improves the density of the target material and greatly reduces the phenomena of over-fast crystal growth, bending deformation, fine cracks and cracking of the target material.

In one specific example, the prefiring temperature can be 1170 ℃ to 1230 ℃, or 1180 ℃, 1190 ℃, 1200 ℃, 1210 ℃, 1220 ℃; in the pre-sintering temperature range, the alkaline earth carbonate can be thoroughly decomposed, so that the solid phase reaction is thoroughly carried out, and the generation of impure phases except the target phase is avoided; meanwhile, crystal grains can not grow excessively, so that the crystal grains are bonded into porcelain to form a hard block which cannot be broken by secondary ball milling, and therefore, the uniform distribution of target material components is facilitated.

In one specific example, the sintering temperature can be, for example, 1220 ℃ to 1280 ℃, and can also be, for example, 1230 ℃, 1240 ℃, 1250 ℃, 1260 ℃, 1270 ℃; if the sintering temperature is too low, crystal grains can not be effectively bonded, so that the mechanical strength, hardness, density and the like are unqualified, and a qualified ceramic target can not be formed; the sintering temperature is too high, which can cause the surface of the ceramic to form a disordered glass structure and other molten phases which affect the performance of products.

In one specific example, the ratio of the amounts of the neodymium oxide, alkaline earth carbonate, and nickel oxide species is: x is 1, and chemical impurity phases except the target phase are avoided.

In a specific example, the first ball milling and/or the second ball milling is wet ball milling, the solvent is at least one of absolute ethyl alcohol and deionized water, the milling medium is at least one of zirconia and alumina, and the diameter of the milling medium is 0.5 mm-2 mm.

In a specific example, the raw materials are dried after wet ball milling to remove the solvent introduced during the ball milling, the drying temperature is 110 ℃ to 130 ℃, and the drying time is 6h to 10h.

In one specific example, the raw materials or the second intermediate comprise, by mass, solvent, mill media = (0.8-1.2), (0.8-1.2), and (1.8-2.2); the ball milling is carried out within the range of the preset proportion, so that the particle size of the raw material powder after ball milling is within the required range, the particle size distribution is narrow, and the particle surface is regular and smooth.

In a specific example, the binder used for granulating in step S3 is at least one of polyvinyl alcohol solution, polyvinylpyrrolidone and polyethylene glycol; the specific surface area of the superfine raw material particles after ball milling is large, the fluidity is poor, and the fluidity of the superfine raw material particles can be improved by using the binder, so that the problems of cavities, incompact corners, lamination cracks, elastic failure and the like of a formed part can be avoided during forming; meanwhile, the ceramic material has certain viscosity, so that the mechanical strength of the green body can be improved, and the green body is not easy to crack during sintering.

In a specific example, the amount of the binder is 1 to 5 percent of the mass of the raw materials. The excessive using amount of the binder can influence the flowability of the powder, thereby influencing the molding quality, and causing the problems of cavities, incompact corners, layer cracks, elastic failure and the like of the molded part; if the amount of the binder is too small, the viscosity is not enough, the mechanical strength of the green body cannot be effectively improved, and the green body is easy to crack during sintering.

In one specific example, the particle size of the third intermediate in step S3 is 60 to 140 mesh. If the particle size distribution is too wide, the uniformity is not sufficient, the inside cannot be uniformly pressed during molding, and the target material is easy to crack.

In a specific example, in the step S4, the target green body is prepared by pressure forming the third intermediate, the pressure is 20MPa to 40MPa, and the pressing time is 10min to 14min; if the pressure is too low and the pressing time is not enough, the density of the green body formed by pressing is low, and the binder cannot effectively bind the raw material, so that the density of the ceramic target material obtained by final sintering is too low; if the pressure is too high or the pressing time is too long, the target material is easy to crack, and the difficulty of demoulding is increased.

In a specific example, the temperature of the glue discharging treatment in the step S4 is 400-600 ℃, and the time is 2-4 h; when the binder removal temperature is too low and the binder removal time is too short, the binder cannot be smoothly volatilized, so that a blank body is deformed and cracked in the subsequent sintering process, and in addition, the carbon content in the binder is high, so that the sintering quality is influenced when oxygen is insufficient to form a reducing atmosphere; if the binder removal temperature is too high and the time is too long, the blank body can be locally sintered, and the quality of the finally prepared ceramic target material can be affected.

In one specific example, after the temperature is reduced to room temperature in a programmed way, the surface is polished, and then the Nd is cleaned by ultrasonic and dried to obtain the Nd which can be directly used _1-x A _x NiO ₃ A ceramic target material.

The Nd with pure components, uniform distribution of elements and density, good mechanical strength, hardness and compactness is prepared by the production process of ball milling, pre-sintering, secondary ball milling, granulation, blank making, glue discharging, programmed heating and sintering and programmed cooling _1-x A _x NiO ₃ A ceramic target material. Ball milling is carried out before solid-phase reaction, so that the raw materials can be mixed more uniformly; the proper pre-sintering temperature and time can ensure that the decomposition of carbonate is more thorough when a solid phase reaction occurs, other impure phases are not generated, and simultaneously, crystal grains with proper size can be obtained, thereby avoiding the influence of overlarge crystal grains and even ceramic bonding on secondary ball milling; ball milling is carried out again before blank making, so that solid phase reaction can be achievedThe obtained ceramic material has smaller particle size and more uniform distribution, and the ceramic material with poor fluidity caused by smaller particle size after ball milling can have better fluidity through granulation, so that a high-quality green body is prepared; the binder removal treatment improves the sintering quality of the green body and avoids deformation and cracking of the green body; the programmed heating is adopted, so that the thermal stress in the sintering process is reduced, and the target material density is uniformly distributed; the proper sintering temperature and time are set, so that the ceramic target material obtained by sintering has good mechanical strength, hardness and compactness.

The invention also provides Nd prepared by the preparation method _1-x A _x NiO ₃ (A = Ca or Sr or Ba,0 < x < 1) target material, and Nd can be obtained by carrying out magnetron sputtering growth on the target material _1-x A _x NiO ₃ Thin films having good crystallinity and high quality single crystal epitaxial properties.

The invention also provides an Nd _1-x A _x NiO ₂ Film having excellent superconducting characteristics and electric transport properties, nd produced by the above production method _1-x A _x NiO ₃ The film is obtained by reducing calcium hydride powder:

(1) 0.4g to 0.6g of calcium hydride powder is arranged at the bottom of a quartz tube, and the tin foil is wrapped with Nd _1-x A _x NiO ₃ Placing the film into a quartz tube, preventing the surface of the film from being stained with calcium hydride powder, and pumping out air in the quartz tube for tube sealing treatment;

(2) Putting the treated quartz tube into a muffle furnace, heating to 270-290 ℃ at the speed of 8-12 ℃/min, keeping the temperature for 1.5-2.5 h, cooling and opening the tube to obtain Nd _1-x A _x NiO ₂ A film.

The present invention will be described in further detail with reference to specific examples and comparative examples. It is understood that the following examples are specific to the apparatus and materials used, and in other embodiments, the invention is not limited thereto, and may be, for example, not limited to ball milling using a planetary ball mill, or to calcination using a muffle furnace, or to polishing using a metallo-polishing machine.

Example 1

(1) And ultrasonically cleaning all used utensils by adopting deionized water or absolute ethyl alcohol. Respectively weighing neodymium oxide, strontium carbonate and nickel oxide according to the mass ratio of 0.8 to 0.2, placing the raw materials, absolute ethyl alcohol and zirconia balls (mass ratio: raw materials: absolute ethyl alcohol: zirconia balls = 1;

(2) Putting the dried powder into a crucible, and placing the crucible in a muffle furnace for presintering at 1200 ℃ for 8h;

(3) Taking the pre-sintered powder as a raw material, performing secondary ball milling and drying according to the parameter setting in the step (1), granulating the dried powder by using a polyvinyl alcohol solution with the mass fraction of 5%, wherein the addition of the polyvinyl alcohol solution is 3% of the mass of the powder, and sieving the powder after the granulation is finished to ensure that the particle size is distributed between 60 and 140 meshes;

(4) Filling the sieved powder into a 2-inch target mold, pressing for 12min under 30MPa, and then demolding and drying to prepare a target green body; gluing the target green body at 500 ℃ for 2h;

(5) Heating the target green compact after the binder removal to 900 ℃ at the speed of 10 ℃/min, keeping the temperature for 1h, heating to 1300 ℃ at the heating rate of 3 ℃/min, and carrying out heat preservation sintering for 4h; then reducing the temperature to 900 ℃ at the cooling rate of 3 ℃/min, and finally cooling to room temperature along with air to obtain a cooled target material;

(6) Polishing the outer surface of the cooled target by adopting a metallographic polishing machine, then ultrasonically cleaning by using absolute ethyl alcohol and drying to obtain clean Nd _0.8 Sr _0.2 NiO ₃ A target material.

(7) Using Nd _0.8 Sr _0.2 NiO ₃ Performing radio frequency magnetron sputtering on the target material, and performing SrTiO sputtering at the temperature of 550 ℃ and the oxygen pressure of 0.02Torr ₃ (001) Growing Nd for single crystal substrates _0.8 Sr _0.2 NiO ₃ A film.

Example 2

(1) And ultrasonically cleaning all the using utensils by using deionized water or absolute ethyl alcohol. Respectively weighing neodymium oxide, barium carbonate and nickel oxide as raw materials, placing the raw materials, absolute ethyl alcohol and alumina balls (mass ratio: raw materials: absolute ethyl alcohol: alumina balls =0.9 = 1;

(2) Putting the dried powder into a crucible, and placing the crucible in a muffle furnace for presintering, wherein the presintering temperature is 1250 ℃, and the presintering time is 7 hours;

(3) Performing secondary ball milling and drying on the pre-sintered powder serving as a raw material according to the parameter setting in the step (1), granulating the dried powder by using polyvinylpyrrolidone, wherein the addition amount of a polyvinyl alcohol solution is 2% of the mass of the powder, and sieving the powder after granulation is completed to ensure that the particle size is distributed between 60 and 140 meshes;

(4) Filling the sieved powder into a 2-inch target mold, pressing for 10min under 35MPa, demolding, and drying to obtain a target green body; gluing the target green body at 400 ℃ for 3h;

(5) Heating the target green body after glue discharging to 900 ℃ at the speed of 8 ℃/min, keeping the temperature for 1h, heating to 1200 ℃ at the heating rate of 4 ℃/min, and carrying out heat preservation sintering for 2h; then the temperature is reduced to 900 ℃ at the rate of 4 ℃/min, and finally the target material is cooled to room temperature along with air to obtain a cooled target material;

(6) Polishing the outer surface of the cooled target by adopting a metallographic polishing machine, then ultrasonically cleaning the polished target by using absolute ethyl alcohol and drying the cleaned target to obtain clean Nd _0.8 Ba _0.2 NiO ₃ A target material.

(7) Using Nd _0.8 Ba _0.2 NiO ₃ Performing radio frequency magnetron sputtering on the target material, and performing SrTiO sputtering at the temperature of 550 ℃ and the oxygen pressure of 0.02Torr ₃ (001) Growing Nd for single crystal substrates _0.8 Ba _0.2 NiO ₃ A film.

Example 3

(1) 0.5g of calcium hydride powder (98.5% by weight metals basis (Mg removed), mg<1%) of the mixture is placed at the bottom of a quartz tube and lightly wrapped by tinfoilNd wrapped-grown on a 0.5cm by 0.05cm strontium titanate substrate _1-x A _x NiO ₃ A film is put into a quartz tube, calcium hydride powder is prevented from being attached to the surface of the film, and the tube sealing treatment is carried out after air in the quartz tube is pumped out;

(2) Putting the treated quartz tube into a muffle furnace, heating to 280 ℃ at the speed of 10 ℃/min, keeping the temperature for 2h, cooling and opening the tube to obtain Nd _1-x A _x NiO ₂ A film.

As shown in FIG. 1, nd was scanned using Energy Dispersive X-Ray Spectroscopy (EDX) element plane in a Scanning Electron Microscope (SEM) _0.8 Sr _0.2 NiO ₃ The target material shows that: the elements of O, ni, sr and Nd of the target material are uniformly distributed, and the components of the target material are pure.

As shown in FIG. 2, for Nd _0.8 Sr _0.2 NiO ₃ And (5) characterizing the film. Wherein FIG. 2 (a) shows Nd _0.8 Sr _0.2 NiO ₃ The diffraction peak of the (002) crystal face of the film, with a significant satellite peak seen to the right of the main peak of the film, is generally observed only when the film has an extremely high single crystal quality and a low surface/interface roughness. FIG. 2 (b) shows Nd _0.8 Sr _0.2 NiO ₃ Rocking curve of (002) crystal plane of thin film, full width at half maximum (FWHM) of only 0.1298 °, with narrower full width at half maximum indicating Nd obtained by sputtering prepared target _0.8 Sr _0.2 NiO ₃ The film crystallinity is good. Meanwhile, phi scanning and asymmetric reciprocal space scanning of HRXRD prove that the film has high-quality single crystal epitaxial property. Thus, high quality Nd obtained by sputtering the preparation method of the invention _0.8 Sr _0.2 NiO ₃ Nd prepared from target material _0.8 Sr _0.2 NiO ₃ The film has good epitaxial crystallinity and high-quality single crystal epitaxial property, and lays a material foundation for the preparation of the nickel-based superconducting film.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. Nd (Nd) _1-x A _x NiO ₂ The preparation method of the superconducting film is characterized by comprising the following steps:

nd is coated by magnetron sputtering coating process _1-x A _x NiO ₃ Nd prepared from target material _1-x A _x NiO ₃ Film of said Nd _1- _x A _x NiO ₃ Performing reduction treatment on the film to obtain the Nd _1-x A _x NiO ₂ A superconducting thin film;

wherein A = Ca or Sr or Ba,0 < x < 1;

the Nd _1-x A _x NiO ₃ The preparation method of the target comprises the following steps:

s2, pre-burning the first intermediate at 1150-1250 ℃ for 7-9 h to prepare a second intermediate;

s5, heating the fourth intermediate to a sintering temperature by a program, sintering, and cooling to room temperature by the program; the sintering temperature is 1200-1300 ℃, and the sintering time is 2-4 h; the programmed temperature rise comprises: heating the green body to 850-950 ℃ at a speed of 5-10 ℃/min, keeping the temperature for 0.8-1.2 h, and then heating to the sintering temperature at a heating rate of 2-4 ℃/min; the programmed cooling comprises: at the sintering temperature, firstly reducing the temperature to 850-950 ℃ at the cooling rate of 2-4 ℃/min, and then reducing the temperature to room temperature;

the reduction treatment comprises the following steps:

(1) 0.4g to 0.6g of calcium hydride powder is put at the bottom of a quartz tube, and Nd is wrapped by tinfoil _1-x A _x NiO ₃ The film is put into a quartz tube and the Nd is avoided _1-x A _x NiO ₃ The surface of the film is stuck with calcium hydride powder, and the air in the quartz tube is pumped out for tube sealing treatment;

(2) Putting the quartz tube treated in the step (1) into a muffle furnace, heating to 270-290 ℃ at the speed of 8-12 ℃/min, keeping the temperature for 1.5-2.5 h, and then cooling and opening the tube to obtain the Nd _1-x A _x NiO ₂ A superconducting thin film.

2. The method according to claim 1, wherein the ratio of the amounts of the neodymium oxide, the alkaline earth carbonate, and the nickel oxide in S1 is: (1-x) x:1.

3. The preparation method according to claim 1, wherein the first ball milling and/or the second ball milling is wet ball milling, the solvent is at least one selected from absolute ethyl alcohol and deionized water, the milling medium is at least one selected from zirconia and alumina, and the diameter of the milling medium is 0.5 mm-2 mm.

4. The preparation method according to claim 3, characterized in that the raw material or the second intermediate is the solvent in parts by mass, the grinding media is (0.8 to 1.2) to (1.8 to 2.2).

5. The method according to claim 1, wherein the binder used for the granulation in S3 is at least one of a polyvinyl alcohol solution, polyvinyl pyrrolidone, and polyethylene glycol.

6. The preparation method of claim 5, wherein the amount of the binder is 1-5% by mass of the raw materials.

7. The preparation method according to claim 1, wherein the particle size of the third intermediate in S3 is 60 to 140 meshes.

8. The preparation method according to claim 1, wherein in S4, the target green compact is prepared from the third intermediate through pressure forming, the pressure is 20 to 40MPa, and the pressing time is 10 to 14min.

9. The preparation method of claim 1, wherein the temperature of the glue discharging treatment in S4 is 400-600 ℃, and the time is 2-4 h.

10. Nd produced by the production method according to any one of claims 1 to 9 _1-x A _x NiO ₂ A superconducting thin film.