Synthetic magnetoelectric coupling in a nanocomposite multiferroic.

P Jain,C Urban,M R Fitzsimmons,V Lauter,A Glavic,J Zhu,Q Wang,Q X Jia,M Varela,Z Bi,M Roldan,T Ahmed

doi:10.1038/srep09089

Abstract

Given the paucity of single phase multiferroic materials (with large ferromagnetic moment), composite systems seem an attractive solution to realize magnetoelectric coupling between ferromagnetic and ferroelectric order parameters. Despite having antiferromagnetic order, BiFeO3 (BFO) has nevertheless been a key material due to excellent 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, an insulating superlattice, is demonstrated using polarized neutron reflectometry. 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, controlled creation of magnetic moment in BFO is a much needed path toward design and implementation of integrated oxide devices for next generation magnetoelectric data storage platforms.

Highlights

Given the paucity of single phase multiferroic materials, composite systems seem an attractive solution to realize magnetoelectric coupling between ferromagnetic and ferroelectric order parameters
The ability to control magnetization, M, via electric fields or alternatively electric polarization, P, via magnetic fields enables a myriad of technological innovations in information storage, sensing, and computing
Exchange bias is the shift of the ferromagnetic hysteresis loop about zero applied magnetic field that can be observed for ferromagnetic/antiferromagnetic composites

Summary

Synthetic magnetoelectric coupling in a nanocomposite multiferroic

Given the paucity of single phase multiferroic materials (with large ferromagnetic moment), composite systems seem an attractive solution to realize magnetoelectric coupling between ferromagnetic and ferroelectric order parameters. BiFeO3 (BFO) has been a key material due to excellent 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, an insulating superlattice, is demonstrated using polarized neutron reflectometry. The magnetization enables magnetic field to change the dielectric properties of the superlattice, which we cite as an example of synthetic magnetoelectric coupling. Controlled creation of magnetic moment in BFO is a much needed path toward design and implementation of integrated oxide devices for generation magnetoelectric data storage platforms

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