Evolution of magnetic and dielectric properties in Sr-substituted high temperature multiferroic YBaCuFeO5

TL;DR

This study investigates how substituting Sr for Ba in YBaCuFeO5 affects its magnetic and dielectric properties, revealing decoupling of transitions and changes in magnetodielectric coupling due to chemical pressure.

Contribution

It provides new insights into how Sr substitution influences the multiferroic behavior and coupling mechanisms in YBaCuFeO5, a high-temperature multiferroic compound.

Findings

Sr substitution shifts magnetic transition to higher temperatures.

Dielectric transition shifts to lower temperatures with Sr.

Magnetodielectric coupling nature changes across the series.

Abstract

We report the evolution of structural, magnetic and dielectric properties due to partial substitution of Ba by Sr in the high temperature multiferroic YBaCuFeO5. This compound exhibits ferroelectric and antiferromagnetic transitions around 200 K and these two phenomena are presumed to be coupled with each other. Our studies on magnetic and dielectric properties of the YBa1-xSrxCuFeO5 (x = 0.0, 0.25 and 0.5) show that substitution of Sr shifts magnetic transition towards higher temperature whereas dielectric transition to lower temperature. These results points to the fact that magnetic and dielectric transitions get decoupled as a result of chemical pressure in form of Sr substitution. The nature of magnetodielectric coupling changes across the series with the presence of higher order coupling terms. Additionally in these compounds glassy dynamics of electric dipoles is observed at low temperatures.