Multiferroicity in a spin-chain compound, Tb2BaCoO5, with exceptionally large magnetodielectric coupling in polycrystalline form

TL;DR

This study uncovers a new multiferroic spin-chain compound, Tb2BaCoO5, exhibiting the largest magnetodielectric effect in polycrystalline form, with potential for room-temperature applications due to its significant coupling properties.

Contribution

It reports the discovery of multiferroicity and an exceptionally large magnetodielectric effect in Tb2BaCoO5, a previously unexplored spin-chain cobaltate, highlighting its potential for practical applications.

Findings

Antiferromagnetic transition at 18.8 K

Largest magnetodielectric effect (~55%) in polycrystals below 10 K

Spin-reorientation observed under magnetic field

Abstract

We report the results of detailed investigations of magnetization, heat-capacity, dielectric, pyrocurrent, and magneto(di)electric measurements on Tb2BaCoO5, belonging to a hither-to-unexplored spin-chain cobaltates family, R2BaCoO5 (R= Rare-earths). The magnetic measurements reveal that this compound exhibits an antiferromagnetic transition at (T_N=) 18.8 K and there is a spin-reorientation beyond 40 kOe below T_N. Dielectric and pyrocurrent data measured as a function of temperature and magnetic-field establish that this compound is a type-II multiferroic material. The most fascinating finding which we would like to emphasize is that the observed value of the magnetodielectric effect beyond the metamagnetic transition field is the largest (close to 55%, below 10 K, for H= 100 kOe) ever reported for polycrystals of a compound in bulk form, thereby offering a hope to find a single-phase polycrystalline compound at room temperature to enable ease of applications.