Heat-capacity anomalies in the presence of high magnetic fields in the spin-chain compound, Ca3Co2O6

TL;DR

This study investigates heat capacity in Ca3Co2O6 under high magnetic fields, revealing unusual shifts in magnetic transition temperatures and subtle magnetic structure changes, challenging typical antiferromagnetic behavior.

Contribution

It provides new insights into the magnetic and thermal behavior of Ca3Co2O6 under high magnetic fields, highlighting anomalies in magnetic transitions.

Findings

Shift of magnetic transition around 24 K with field increase

Absence of magnetic peak near 10 K in heat capacity

Hysteresis indicates subtle magnetic structure change

Abstract

Heat-capacity behavior in the presence of externally applied magnetic field (H) up to 140 kOe is investigated (2-35 K) for the quasi-1-dimensional compound, Ca3Co2O6, believed to order magnetically with the so-called partially disordered anti-ferromagnetic structure. The results reveal that there is a shift of the magnetic transition occurring around 24 K to a marginally higher temperature (by 0.5 K) as H is increased from 10 to 30 kOe, uncharacteristic of anti-ferromagnets. No peak attributable to magnetic ordering could be observed in the entire field range of investigation in the vicinity of the second magnetic transition, occurring around 10 K. However, hysteresis studies of H-dependence of C indicate a subtle change in the magnetic structure as the T is lowered across 10 K.