Anomalous temperature evolution of the internal magnetic field distribution in the charge-ordered triangular antiferromagnet AgNiO2

TL;DR

This study investigates the unusual temperature-dependent behavior of the internal magnetic field distribution in the charge-ordered triangular antiferromagnet AgNiO2 using muon-spin relaxation, revealing complex magnetic sublattice dynamics.

Contribution

It provides a detailed analysis of muon precession frequencies and proposes a model explaining the anomalous temperature evolution of magnetic fields in AgNiO2.

Findings

Six distinct muon precession frequencies observed below T_N

Precession frequencies exhibit unusual temperature dependence

Evidence suggests separate evolution of two magnetic sublattices

Abstract

Zero-field muon-spin relaxation measurements of the frustrated triangular quantum magnet AgNiO2 are consistent with a model of charge disproportionation that has been advanced to explain the structural and magnetic properties of this compound. Below an ordering temperature of T_N=19.9(2) K we observe six distinct muon precession frequencies, due to the magnetic order, which can be accounted for with a model describing the probable muon sites. The precession frequencies show an unusual temperature evolution which is suggestive of the separate evolution of two opposing magnetic sublattices.