Self-resonant Coil for Contactless Electrical Conductivity Measurement under Pulsed Ultra-high Magnetic Fields

TL;DR

This paper introduces a contactless method using a self-resonant coil to measure electrical conductivity in materials under pulsed ultra-high magnetic fields exceeding 100 T, enabling precise analysis of superconductors.

Contribution

The study develops a novel high-frequency circuit apparatus for conductivity measurements under extreme magnetic fields, demonstrating its effectiveness on a high-temperature superconductor.

Findings

Successfully measured conductivity changes up to 102 T

Determined the upper critical field with high accuracy

Validated the apparatus with a cuprate superconductor

Abstract

In this study, we develop experimental apparatus for contactless electrical conductivity measurements under pulsed high magnetic fields over 100 T using a self-resonant-type high-frequency circuit. The resonant power spectra were numerically analyzed, and the conducted simulations showed that the apparatus is optimal for electrical conductivity measurements of materials with high electrical conductivity. The newly developed instruments were applied to a high-temperature cuprate superconductor La$_{2-x}$Sr$_x$CuO$_4$ to show conductivity changes in magnetic fields up to 102 T with a good signal-to-noise ratio. The upper critical field was determined with high accuracy.