Magnetic field enhanced structural instability in EuTiO_{3}

TL;DR

This study demonstrates that applying an external magnetic field can increase the transition temperature of EuTiO_{3}'s structural phase change, aligning with theoretical models of spin-phonon interactions.

Contribution

It reveals magnetic field control over EuTiO_{3}'s structural transition temperature, supported by experimental data and theoretical modeling.

Findings

Magnetic field raises the transition temperature by 4 K at 9 T.

Transition involves oxygen octahedra rotation driven by zone boundary phonon softening.

Results agree with coupled spin-phonon interaction theory.

Abstract

EuTiO_{3} undergoes a structural phase transition from cubic to tetragonal at T_S = 282 K which is not accompanied by any long range magnetic order. However, it is related to the oxygen ocathedra rotation driven by a zone boundary acoustic mode softening. Here we show that this displacive second order structural phase transition can be shifted to higher temperatures by the application of an external magnetic field (increased by 4 K for mu_{0}H = 9 T). This observed field dependence is in agreement with theoretical predictions based on a coupled spin-anharmonic-phonon interaction model.