Preparation method of tl-2223 superconducting thin film

Abstract

The invention discloses a preparation method of a Tl-2223 superconducting thin film. Silver foil or gold foil is used to seal and wrap an amorphous precursor film containing thallium and a burning target containing thallium, and place the film in a sealed argon or oxygen flow environment. Sintering; wherein, the metal ion molar ratio of Tl, Ba, Ca, Cu of the amorphous precursor film containing thallium is 2.4~4.5:2:2:3.2~3.8; Tl:Ba:Ca:Cu=0.8~1.2:2:1~2:2~3 Ba, Ca, Cu oxides and Tl 2 o 3 Made by sintering. The present invention can quickly cross the phase forming temperature zone of Tl-1212, Tl-2212, Tl-1223 and other low-temperature phases, and directly reach the superconducting phase temperature zone of Tl-2223, thereby preparing a pure-phase film, which has heating and cooling time and constant temperature time Advantages of short length and low production cost.

Description

technical field [0001] The invention relates to the field of thallium superconducting thin film materials. More specifically, the present invention relates to a preparation method of Tl-2223 superconducting thin film. Background technique [0002] Tl 2 Ba 2 Ca 2 Cu 3 o 10 (Tl-2223) superconductor has a high superconducting transition temperature (125K) and a high upper critical magnetic field. It is a material that can realize superconducting power transmission in the temperature range of liquefied natural gas. It is used in the field of weak and strong electricity has great potential value. [0003] In the current research on the synthesis of Tl-2223 thin films, the main methods for preparing precursor films include pulsed laser deposition, ultrasonic spray pyrolysis technology, magnetron sputtering, etc. These research processes have something in common: traditional sintering equipment has a low heating rate, usually 1-10°C / min, that is, 0.017-0.16°C / s. This method...

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Problems solved by technology

These research processes have something in common: traditional sintering equipment has a low heating rate, usually 1-10°C / min, that is, 0.017-0.16°C / s

This method obviously has a disadvantage: the Tl system has multiple superconducting phases with different phase formation temperatures, and the phase formation temperature of Tl-2223 is higher than that of Tl-1212, Tl-2212, and Tl-1223. The low heating rate makes the precursor film go through the Tl-1212, Tl-2212, Tl-1223 phase formation temperature zone for a long time during the heating process. Therefore, superconducting phases such as Tl-1212 and Tl-2212 are first formed during the heating process. As a result, it is difficult to eliminate these impurity phases when the phase formation temperature of Tl-2223 is reached, and what is obtained is a mixed phase film

These methods can effectively improve the purity of the phase, but there are still a small amount of grains of other phases, and the preparation cycle of a single sample is increased (generally 2 to 5 days), which increases the production cost.

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