Synthetic magnetoelectric coupling in a nanocomposite multiferroic

Abstract

Given the paucity of single phase multiferroic materials (with large ferromagnetic moment), composite systems seem an attractive solution in the quest to realize magnetoelectric cou-pling between ferromagnetic and ferroelectric order parameters. Despite having antiferro-magnetic order, BiFeO3 (BFO) has nevertheless been a key material in this quest due to excel-lent ferroelectric properties at room temperature. We studied a superlattice composed of 8 repetitions of 6 unit cells of La0.7Sr0.3MnO3 (LSMO) grown on 5 unit cells of BFO. Significant net uncompensated magnetization in BFO is demonstrated using polarized neutron reflectometry in an insulating superlattice. Remarkably, the magnetization enables magnetic field to change the dielectric properties of the superlattice, which we cite as an example of synthetic magnetoelectric coupling. Importantly, this controlled creation of magnetic moment in BFO suggests a much needed path forward for the design and implementation of integrated oxide devices for next generation magnetoelectric data storage platforms.