Microwave Hall effect measurement for materials in the skin depth region

TL;DR

This paper introduces a novel microwave Hall effect measurement technique using a cross-shaped bimodal cavity, enabling accurate Hall angle measurements in materials within the skin depth region at low temperatures, including superconductors.

Contribution

The paper presents a new microwave Hall effect measurement method that simplifies Hall angle measurements at cryogenic temperatures without complex tuning, applicable to skin depth materials.

Findings

Microwave Hall angles in Bi single crystals match DC Hall angles.

The method works effectively at low temperatures and in the skin depth region.

It opens new avenues for studying Hall effects in superconductors.

Abstract

We developed a new microwave Hall effect measurement method for materials in the skin depth region at low temperatures using a cross-shaped bimodal cavity. We analytically calculated electromagnetic fields in the cross-shaped cavity, and the response of the cavity including the sample, whose property is represented by the surface impedance tensor; further, we constructed the method to obtain the Hall component of the surface impedance tensor in terms of the change in resonance characteristics. To confirm the validity of the new method, we applied our method to measure the Hall effect in metallic Bi single crystals at low temperatures, and we confirmed that the microwave Hall angles coincide with the DC Hall angle. Thus, it becomes clear that the Hall angle measurement under cryogenic conditions becomes possible without any complicated tuning mechanisms, and our bimodal cavity method can be used to measure the microwave Hall effect on materials in the skin depth region. The result opens a new approach to discuss the Hall effect in condensed matter physics such as the microwave flux-flow Hall effect in superconductors.