The symmetry and magnetoelectric effects in garnet crystals and films

TL;DR

This paper investigates the symmetry and quantum mechanical aspects of magnetoelectric effects in garnet crystals and films, revealing conditions for their occurrence and how magnetic fields can induce electric polarization.

Contribution

It provides a combined symmetry and quantum analysis showing magnetoelectric effects are limited in garnets but can be induced under specific conditions, including magnetic field effects.

Findings

Magnetoelectric effect is generally absent in garnets despite antisymmetry conditions.

Magnetic fields can induce antiferroelectric structures and electric polarization.

Electric polarization can be generated by inhomogeneous magnetic fields in bulk crystals.

Abstract

The magnetoelectricity of garnets is considered by means of a symmetry and quantum mechanical combined analysis. It is shown, that the magnetoelectric effect is not realized in most garnets although the necessary condition of the crystal magnetic structure antisymmetry in them is held at low temperatures. Nevertheless, the effect can be observed in some garnets as well as other odd effects, namely, piezomagnetic effect, magnetic field evoked piezoelectric one, etc. It is also discovered that magnetic fields can induce specific antiferroelectric structures in garnet crystals and produce electric polarization in epitaxial films. The polarization can also be caused in a bulk crystal by an inhomogeneous magnetic field.