Muon Spin Spectroscopy evidence of the violation of Anderson condition in magnetite

TL;DR

This study uses muon spin spectroscopy to investigate charge localization and dynamics in magnetite, revealing violations of the Anderson condition and fluctuations near the Verwey transition.

Contribution

It provides experimental evidence of Anderson condition violation and charge fluctuations in magnetite using muon spectroscopy, offering new insights into its electronic state.

Findings

Different spin precession patterns across temperature ranges

Good agreement with a model involving localized charges violating Anderson condition

Detection of charge fluctuations above the Verwey temperature

Abstract

We present new muon spectroscopy data on a Fe$_3$O$_4$ single crystal, revealing different spin precession patterns in five distinct temperature ranges. A careful analysis of the local field and its straightforward modeling obtains surprisingly good agreement with experiments only if a very specific model of localized charges violating Anderson condition, and a correlated muon local dynamics are implemented. Muon evidence for fluctuations just above the Verwey temperature, precursor of the low temperature charge localized state, is provided.