Low field magnetoelectric effect in Fe substituted Co4Nb2O9

TL;DR

This study explores the magnetoelectric properties of Fe substituted Co4Nb2O9, revealing enhanced low-field magnetoelectric coupling and new magnetic transitions, expanding potential applications in low-field magnetic sensors.

Contribution

It reports the first observation of low-field magnetoelectric effects in Fe substituted Co4Nb2O9, demonstrating significant coupling at fields below the spin flop threshold.

Findings

Magnetoelectric coupling observed at fields as low as 0.25 T

Fe substitution induces additional magnetic transitions

Enhanced ferroelectric behavior in Fe substituted samples

Abstract

Co4Nb2O9 (CNO) having {\alpha}-Al2O3 crystal structure with Co chains along c-direction shows gigantic magnetoelelctric coupling below antiferromagnetic ordering temperature of 27 K but above a spin flop field of 1.6 T. We have investigated structural, magnetic and magnetoelectric properties of Fe substituted (10% and 20%) samples and compared with the parent one. In fact magnetic and specific heat measurements have revealed an additional magnetic transition below 10 K and presence of short range magnetic ordering above ~ 50 K in parent as well as in Fe substituted samples. Linear magnetoelelctric and ferroelectric behaviours are evidenced in the Fe substituted samples where an electric field of 5 kV/m is sufficient to align the dipoles and the magnetoelelctric coupling is ensured for magnetic fields as low as 0.25 T, far below the spin flop field.