Control of ferroelectric phase by chemical pressure in (Gd,Tb)MnO$_{3}$ crystals

TL;DR

This study explores how chemical substitution influences ferroelectric phases in Gd-Tb manganite crystals, revealing phase boundaries and transitions under magnetic fields, advancing understanding of multiferroic behavior.

Contribution

It identifies the compositional phase boundary between two ferroelectric phases and maps the electric and magnetic phase diagrams under magnetic fields.

Findings

Phase boundary between GdMnO3-type and TbMnO3-type ferroelectric phases around x=0.3-0.4.

Successive ferroelectric phase transitions in x=0.1 under magnetic fields above 3T.

Detailed phase diagrams for x=0, 0.1, and 0.3 in temperature-field space.

Abstract

We have investigated the dielectric properties of Gd$_{1-x}$Tb$_{x}$MnO$_{3}$ crystals in magnetic fields to clarify the crossover between two distinct ferroelectric phases, GdMnO$_{3}$-type (first-order displacive) and TbMnO$_{3}$-type (second-order order-disorder). We have found that the compositional phase boundary between the phases exists around 0.3$<$$x$$<$0.4. For the $x$=0.1 sample exposed to magnetic fields above 3T, we have discovered successive ferroelectric phase transitions that occur at two different temperatures. We have determined the electric and magnetic phase diagram for $x$$=$0, 0.1, and 0.3 in the plane of temperature and field in order to demonstrate the change in the ferroelectric phases.