Method for preparing a-shaft orientated high-temperature superconducting film

Abstract

The invention discloses a method for preparing an a-shaft orientated high-temperature superconducting film. The method comprises the following steps: (a) preparing Ba-Cu-O powder; (b) adding Ba-Cu-O precursor powder into a Y2O3 crucible in a crystal growing furnace, heating to a first temperature, and performing heat preservation to obtain a Y-Ba-Cu-O solution; (c) cooling the solution to a second temperature at a first cooling rate; (d) heating the solution from the second temperature to a third temperature at a first temperature rise rate; (e) adopting an NGO mono-crystal substrate fixedly arranged on a connecting rod as a seed crystal material, and inserting the NGO mono-crystal substrate into a solution obtained in the step (d) to grow a pure a-shaft orientated YBCO liquid phase epitaxial film. According to the method disclosed by the invention, the NGO mono-crystal substrate is adopted as a seed crystal, and the epitaxial growth of an a-shaft oriented YBCO superconducting thick film can be achieved by controlling the first cooling rate, the second temperature, the first temperature rise rate and the third temperature.

Description

technical field [0001] The invention relates to a method for preparing a high-temperature superconducting material, in particular to a method for preparing an a-axis-oriented high-temperature superconducting film by regulating the cooling process of a solution. Background technique [0002] High-temperature superconducting materials have excellent superconducting properties at the temperature of liquid nitrogen, so they have extremely important application values ​​in superconducting energy storage, superconducting motors, nuclear magnetic resonance, and device research and development. The basic and applied research of high-quality membranes has attracted the attention of a large number of materials physicists. At present, high-temperature superconductors mainly include four categories: 90K rare earth system, 110K bismuth system, 125K thallium system and 135K mercury system. Among them, YBa 2 Cu 3 o x (referred to as YBCO, Y123) has a superconducting transition temperat...

AI Technical Summary

Problems solved by technology

However, the existing preparation process mainly has the following two problems: first, it is very difficult to grow pure a-axis films in air

The irreconcilable contradiction between the substrate dissolution effect and the degree of supercooling makes the growth window of a-axis films in the metastable region very small, which brings great difficulties to the preparation of pure a-axis films

In addition, although the growth window in the unstable region is greatly expanded, due to the spontaneous nucleation of the solution, there will be floating on the liquid surface, which will greatly affect the quality of the a-axis film

Second, although the growth window of the a-axis in oxygen is above 10K, the method is cumbersome and expensive

However, studies have shown that none of these methods can obtain a-axis superconducting films, and almost only superconducting films with c-axis or a / c-axis mixed orientation can be obtained, indicating that these methods cannot achieve a minimal supersaturation state. In order to obtain pure a-axis superconducting film, we must find ways to obtain a very small supersaturation state