Realization of giant magnetoelectricity in helimagnets

TL;DR

This paper demonstrates that Al-substitution in helimagnets significantly enhances magnetoelectric properties, enabling electric polarization switching at ultra-low magnetic fields and achieving giant ME susceptibility.

Contribution

It reveals how Al-substitution in Ba0.5Sr1.5Zn2(Fe1-xAlx)12O22 helimagnets tailors low-field ME properties, a novel approach for controlling magnetoelectric effects.

Findings

Critical magnetic field reduced from ~1 T to ~1 mT with Al-substitution.

Giant ME susceptibility of 2.0 x 10^4 ps/m achieved at x=0.08.

Control of orbital moments in Fe sites is key to tuning ME properties.

Abstract

We show that low field magnetoelectric (ME) properties of helimagnets Ba0.5Sr1.5Zn2(Fe1-xAlx)12O22 can be efficiently tailored by Al-substitution level. As x increases, the critical magnetic field for switching electric polarization is systematically reduced from ~1 T down to ~1 mT, and the ME susceptibility is greatly enhanced to reach a giant value of 2.0 x 10^4 ps/m at an optimum x = 0.08. We find that control of nontrivial orbital moment in the octahedral Fe sites through the Al-substitution is crucial for fine tuning of magnetic anisotropy and obtaining the conspicuously improved ME characteristics.