A Simultaneous Magneto-Dielectric Phase Transition in RbCoBr$_3$

TL;DR

This paper models magneto-dielectric phase transitions in layered triangular lattice compounds, revealing that simultaneous transitions occur when magnetic and lattice energy scales align, leading to cooperative ordering.

Contribution

It introduces a coupled spin-lattice model showing simultaneous phase transitions and the disappearance of intermediate phases in ABX3-type compounds.

Findings

Simultaneous magneto-dielectric transition occurs when energy scales match.

Intermediate disordered phases are suppressed in the coupled system.

Spin and lattice systems cooperatively relax frustration and order.

Abstract

We have modeled magneto-dielectric phase transitions in ABX$_3$-type layered triangular lattice compounds. The model consists of a spin system (magnetic transition) and a lattice system (dielectric transition). Magnetic exchange interactions are supposed to change with a relative positionbetween two spins. This assumption produces an effective coupling between the lattice and the spin. Applying the nonequilibrium relaxation method, we have found that a simultaneous magneto-dielectric phase transition occurs when energy scales of the spin part and the lattice part coincide. An intermediate phase like the partial disordered phase disappears. Both systems relax frustration of the other system cooperatively and realize ordered states.