Method for preparing boron-doped YBCO (Yttrium Barium Copper Oxide) superconducting film by one-step heat treatment process

Abstract

The invention discloses a method for preparing a boron-doped YBCO (Yttrium Barium Copper Oxide) superconducting film by a one-step heat treatment process, which belongs to the technical field of materials. With yttrium acetate, barium trifluoroacetate and copper isocaprylate as materials, ethanol as a medium and boric acid as a dopant, the boron-doped YBCO superconducting film is prepared by thermal crystallization. According to the method disclosed by the invention, a boron element is uniformly doped into the YBCO film, the viscosity of precursor solution is increased, the shrinkage of the film in the process of YBCO heat treatment is relieved, consequently, the preparation of the boron-doped YBCO superconducting film by the one-step heat treatment process becomes possible, and the quality of film formation is ensured. In addition, the boric acid is generated into diboron trioxide under the condition of high temperature, which is doped in the produced film to serve as a pinning center in the form of a second phase, and thereby the electric property of the film in a magnetic field is improved. The efficiency of production is high, and the method has a great application prospect.

Description

technical field [0001] The invention belongs to the technical field of materials, in particular to a method for preparing a boron-doped YBCO superconducting film by a one-step heat treatment process. Background technique [0002] YB 2 Cu 3 o 7-x (YBCO) film has broad application prospects due to its high critical current density and critical temperature, high field performance and price advantages. It is widely used in electronic devices and other fields, and has attracted the attention of research groups from various countries in recent years. [0003] The methods for preparing YBCO membranes are mainly divided into physical methods and chemical methods. Physical methods mainly include pulsed laser deposition (PLD), ion beam assisted deposition (IBAD), direct current sputtering (DCS), metal organic chemical vapor deposition (MOCVD) and so on. However, the physical method generally requires expensive equipment, and the YBCO products produced are difficult to market on a ...

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Problems solved by technology

[0004] The preparation of YBCO membrane by MOD method is generally divided into two steps, that is, the configuration of the precursor solution and heat treatment. In the traditional MOD method, the concentration of the precursor solution should not be too large due to the use of copper acetate, between 1.0 and 1.5mol / L. Experiments show that the precursor solution If the concentration is too high, the membrane will rupture during heat treatment, which will affect the quality of the YBCO membrane; the distillation medium of this method is methanol, which is highly toxic and harmful to the human body, which limits the application of this method in the laboratory; due to the low concentration of the precursor solution, The thickness of the film is limited, resulting in the need for at least two coatings, two low-temperature heat treatments and one high-temperature heat treatment to prepare a certain thickness of YBCO film. The preparation time generally reaches more than 48 hours, which is time-consuming and power-consuming, and the preparation efficiency is not high.

[0005] The doping of YBCO film is generally divided into alkali metal doping, Pr doping, and Sn and Zr doping. These methods introduce pinning centers into the YBCO film to constrain the movement of magnetic flux and increase the critical current of the material. Density, so as to effectively improve the physical properties and transition temperature of high-temperature superconductors, but there are more or less problems in the above methods, such as the transition temperature is not significantly improved, the critical current density is not significantly improved, etc.

The boron doping of YBCO film has not been studied yet. Thermogravimetric analysis shows that boric acid decomposes at 107.5°C to form metaboric acid, and metaboric acid decomposes when heated to 150-160°C to form diboron trioxide, which can As a dopant for semiconductors, it can be used as a dopant for superconductors to improve the properties of superconductors. At the same time, too high a concentration of the precursor solution will cause the film to rupture during heat treatment.

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