Magnetic Properties of Spinel FeCr$_{2}$S$_{4}$ in High Magnetic Field

TL;DR

This study investigates the magnetic and orbital phase transitions of FeCr₂S₄ under high magnetic fields, revealing step-like anomalies indicating complex magnetic and orbital ordering phenomena.

Contribution

It provides new insights into the magnetic phase boundary and the coupling between spin structure and lattice in FeCr₂S₄ under high magnetic fields.

Findings

Observation of a step-like anomaly at T_{OO} ~ 9 K in magnetization.

Identification of a magnetic phase boundary at B_c ~ 5.5 T below T_{OO}.

Strong coupling between spin structure and lattice in the orbital ordered phase.

Abstract

We studied temperature and magnetic field dependence of magnetization, $M(T)$ and $M(B)$, on thiospinel FeCr$_{2}$S$_{4}$. We observed a step-like anomaly at $T_{OO} \sim$ 9 K for $M$($T$) attributed to an orbital order transition in magnetic field 0 $< B \leq$ 7 T. Furthermore, also for $M$($B$), an step-like anomaly appears at $B_{c} \sim$ 5.5 T below $T_{OO}$. This suggests an existence of a magnetic phase boundary at $B_{c}$ in $T < T_{OO}$. Because the anomaly at $B_{c}$ of $M(B)$ exists in the orbital ordered phase, the spin structure of FeCr$_{2}$S$_{4}$ in $T\ <\ T_{OO}$ is strongly coupled with the lattice of the system.