Peculiar magnetic dynamics across the in-field transition in Ca3Co2O6

TL;DR

This study investigates the static and dynamic magnetic properties of Ca3Co2O6 across a field-induced transition, revealing distinct magnetic cluster behaviors and energy barriers, enhancing understanding of its complex magnetic phases.

Contribution

It provides a detailed analysis of magnetic dynamics across the transition, highlighting differences in cluster distributions and their field and temperature dependencies, which were previously overlooked.

Findings

High field response shows narrow magnetic cluster distribution with ~200 K energy barrier.

Below 3.5 T, a second magnetic contribution with smaller frequencies and strong dependencies emerges.

The results suggest intra-chain and inter-chain magnetic clustering influences the transition behavior.

Abstract

The discovery of multiple coexisting magnetic phases in a crystallographically homogeneous compound Ca$_3$Co$_2$O$_6$ has stimulated an ongoing research activity. In recent years the main focus has been on the zero field state properties, where exceedingly long time scales have been established. In this study we report a detailed investigation of static and dynamic properties of Ca$_3$Co$_2$O$_6$ across the magnetic field induced transition around 3.5 T. This region has so far been practically neglected while we argue that in some aspects it represents a simpler version of the transition across the $B = 0$ state. Investigating the frequency dependence of the ac susceptibility we reveal that on the high field side ($B > 3.5$ T) the response corresponds to a relatively narrow distribution of magnetic clusters. The distribution appears very weakly dependent on magnetic field, with an associated energy barrier of around 200 K. Below 3.5 T a second contribution arises, with much smaller characteristic frequencies and a strong temperature and magnetic field dependence. We discuss these findings in the context of intra-chain and inter-chain clustering of magnetic moments.