Magnetically tunable dielectric materials

TL;DR

This paper explores how magnetic ordering affects dielectric properties in materials through spin-phonon interactions, highlighting significant magnetodielectric effects in multiferroics like Ni3V2O8.

Contribution

It introduces a model for spin-phonon coupling and demonstrates large magnetodielectric effects at ferroelectric transitions in multiferroic materials.

Findings

Dielectric constant shifts at magnetic transitions due to spin-phonon coupling.

Significant magnetodielectric effects observed in Ni3V2O8.

Model explains the coupling mechanism between spins and phonons.

Abstract

The coupling between localized spins and phonons can lead to shifts in the dielectric constant of insulating materials at magnetic ordering transitions. Studies on isostructural SeCuO3 (ferromagnetic) and TeCuO3 (antiferromagnetic) illustrate how the q-dependent spin-spin correlation function couples to phonon frequencies leading to a shift in the dielectric constant. A model is discussed for this spin-phonon coupling. The magnetodielectric coupling in multiferroic materials can be very large at a ferroelectric transition temperature. This coupling is investigated in the recently identified multiferroic Ni3V2O8.