Nondestructive testing device of critical current of high-temperature superconducting film, and detection method thereof

Abstract

The invention provides a nondestructive testing device of critical current of a high-temperature superconducting film, and a detection method thereof. The composition of the testing device is mainly as follows: a teflon rod is vertically installed in a Dewar on a lower bottom plate, and a circular teflon sheet is fixed at a top end of the teflon rod; cross bars are connected among four upright posts on the lower bottom plate; a longitudinal linear guide rail is fixed on the cross bar on the left side, and a longitudinal laser displacement sensor is fixed at the end part of the longitudinal linear guide rail; a longitudinal slide rail is fixed on the cross bar on the right side; the two ends of a horizontal linear guide rail are fixed on a sliding table and the slide rail of the longitudinal linear guide rail; a horizontal laser displacement sensor is fixed at the end part of the horizontal linear guide rail; the middle lower part of a vertical linear guide rail is fixed on the slidingtable of the horizontal linear guide rail, and a vertical laser displacement sensor is fixed at the top end of the vertical linear guide rail; and the bottom of the sliding table of the vertical linear guide rail is in threaded connection with a fulcrum bar provided with a low temperature Hall probe array at the bottom end, or a vertical fulcrum bar provided with a Helmholtz coil at the bottom. The device can accurately obtain the non-uniformity distribution data of the critical current of the high temperature superconducting film.

Description

technical field [0001] The invention relates to a high-temperature superconducting film critical current detection device and a detection method thereof. Background technique [0002] Superconducting devices prepared by using high-temperature superconducting thin films are widely used in the field of electronics. As one of the basic characteristics of high-temperature superconducting thin films, the critical current of high-temperature superconducting thin films has decisive significance for the stability of working characteristics and power load capacity of superconducting devices. Therefore, it is necessary to detect the critical current of the high temperature superconducting film. [0003] There are two methods for detecting the critical current of the high-temperature superconducting film. The first method is a direct transportation method, that is, the four-lead method. This method requires four electrodes to be physically destroyed on the high-temperature superconduc...

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Problems solved by technology

Its disadvantages are: the production process of the four electrodes is not only cumbersome but also causes irreversible physical damage to the high-temperature superconducting film; if the operation is slightly careless, the current applied by the current source is too large, and the high-temperature superconducting film will be burned

This method has strict requirements on the arrangement position of the detection coil and the excitation coil: if the detection coil and the excitation coil are arranged on both sides of the high-temperature superconducting film, the two coils will be separated due to the Dewar volume and the high-temperature superconducting film. Due to the limitation of the fixed position, it cannot be moved flexibly, so that the critical current on the entire surface of the high-temperature superconducting film cannot be completely measured; and the detection coil and the exciting coil are arranged on the same side of the high-temperature superconducting film, which will make the magnetic field of the exciting coil It directly affects the detection coil. In order to eliminate this effect, it is necessary to add an additional compensation coil or calibrate the collected data to ensure the reliability of the data.

In addition, the detection coil and the excitation coil cannot be made too small due to the limitations of the process and materials, which leads to a large area of ​​the measured critical current, and the exact correspondence between the position of the high-temperature superconducting film and the critical current cannot be obtained ( That is, the non-uniform distribution of the critical current), and then the reason for the low critical current cannot be analyzed, and it is impossible to provide an effective basis for the improvement of the preparation process to increase the critical current of the high-temperature superconducting film.

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