Method and device for measuring non-uniformity of critical current density of surface layer of high-temperature superconducting bulk material

Abstract

The invention discloses a method and a device for measuring non-uniformity of critical current density of a surface layer of a high-temperature superconducting bulk material and belongs to the technical field of magnetic measurement. The measuring device comprises a magnet exciting coil, a secondary coil, a coil bracket, a to-be-measured sample platform, phase-locked amplifiers, a power amplifier, a precision resistor and an impedance regulation resistor; the measuring method comprises the following steps: firstly, fully cooling the to-be-measured sample platform, the magnet exciting coil, the secondary coil and to-be-measured high-temperature superconducting samples in absence of a magnetic field; then calculating to obtain an exciting current peak value and a tertiary harmonic voltage peak value of the secondary coil under the output voltage of each phase-locked amplifier; calculating critical current density values and transmission depths of the to-be-measured high-temperature superconducting samples under the exciting magnetic field strength and drawing a curve. The device and the method can be used for measuring the non-uniformity of critical current density of the surface layer of the high-temperature superconducting bulk material; the measurement error range is 10%; the voltage signals can be measured; the measurement precision is up to 1nV.

Description

technical field [0001] The invention belongs to the technical field of magnetic measurement, and can be applied and extended in the fields of superconducting material research, strong magnet design, magnetic levitation, etc., and specifically relates to a method and device for measuring the non-uniformity of critical current density on the surface of a high-temperature superconducting bulk material. Background technique [0002] With the development of high-temperature superconducting technology, high-temperature superconducting bulk materials are gradually moving towards practicality, and have a wide range of applications in superconducting magnetic levitation trains, magnetic levitation bearings, permanent magnets with strong magnetic fields, superconducting energy storage flywheels and superconducting motors. prospect. The performance parameters involved in these applications mainly depend on the ability of the superconducting material to capture the magnetic field, and i...

AI Technical Summary

Problems solved by technology

The first one is based on the calculation and analysis of the average magnetization of the superconducting block placed in the magnetic susceptibility meter, so the value of the critical current density at different depths from the surface of the high-temperature superconducting block cannot be obtained

The second method currently only measures and analyzes superconducting bulk materials with uniform critical current density characteristics, and does not analyze and characterize the situation due to the inhomogeneity of critical current density distribution in the measurement. Therefore, for superconducting bulk materials Magnetic measurement of the critical current density distribution in the surface layer has not been reported yet

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