In this study, the authors investigate the hysteresis effect of low-field microwave absorption (LFMA) in copper-substituted lead apatite. They find that rotating the samples under an external magnetic field reduces this effect, which cannot be restored by a strong magnetic field but spontaneously recovers after two days. This suggests that the LFMA has glassy characteristics and rules out the possibility of ferromagnetism. The intensity of LFMA decreases sharply at around 250K, indicating a phase transition. The authors propose a lattice gauge model to explain these effects as a transition between the superconducting Meissner phase and vortex glass, including the calculation of the slow dynamics.
https://arxiv.org/abs/2312.10391