Magneto-structural transitions in a frustrated magnet at high fields

TL;DR

This study investigates high-field magneto-structural transitions in the frustrated magnet ZnCr2S4 using ultrasound and magnetization measurements, revealing a sequence of structural states with constant stiffness and continuous magnetization evolution.

Contribution

It provides new insights into the high-field magneto-structural phase diagram of ZnCr2S4, highlighting the sequence of structural states and contrasting behavior with other frustrated spinels.

Findings

Observation of step-like changes in sound velocity indicating structural transitions.

Continuous magnetization without plateaus up to full polarization.

Identification of coexisting spin structures and lattice transformations.

Abstract

Ultrasound and magnetization studies of bond-frustrated ZnCr2S4 spinel are performed in static magnetic fields up to 18 T and in pulsed fields up to 62 T. At temperatures below the antiferromagnetic transition at T_N1 14 K the sound velocity as function of magnetic field reveals a sequence of steps followed by plateaus indicating a succession of crystallographic structures with constant stiffness. At the same time, the magnetization evolves continuously with field up to full magnetic polarization without any plateaus in contrast to geometrically frustrated chromium oxide spinels. The observed high-field magneto-structural states are discussed within a H-T phase diagram taking into account the field and temperature evolution of three coexisting spin structures and subsequent lattice transformations induced by magnetic field.