Strange memory effect of low-field microwave absorption in copper-substituted lead apatite

TL;DR

This paper reports a hysteresis effect in low-field microwave absorption in copper-substituted lead apatite, revealing a glassy transition between superconducting and vortex glass phases with slow dynamics and temperature-dependent behavior.

Contribution

It introduces a lattice gauge model to explain the transition and slow dynamics of LFMA effects, highlighting a novel glassy behavior in this material.

Findings

LFMA exhibits hysteresis and spontaneous recovery after two days.

A sharp decrease in LFMA at 250K indicates a phase transition.

The lattice gauge model links effects to superconducting and vortex glass transition.

Abstract

We observe a considerable hysteresis effect of low-field microwave absorption (LFMA) in copper-substituted lead apatite. By continuously rotating samples under external magnetic field, this effect is diminished which can not be renewed by a strong magnetic field but will be spontaneously recovered after two days, indicating its glassy features and excluding possibility of any ferromagnetism. The intensity of LFMA is found to sharply decrease at around 250K, suggesting a phase transition takes place. A lattice gauge model is then employed to assign these effects to the transition between superconducting Meissner phase and vortex glass, and the slow dynamics wherein is calculated as well.