title: Stabilization of weak ferromagnetism by strong magnetic response to epitaxial strain in multiferroic BiFeO3.
abstract: Multiferroic BiFeO3 exhibits excellent magnetoelectric coupling critical for magnetic information processing with minimal power consumption. However, the degenerate nature of the easy spin axis in the (111) plane presents roadblocks for real world applications. Here, we explore the stabilization and switchability of the weak ferromagnetic moments under applied epitaxial strain using a combination of first-principles calculations and group-theoretic analyses. We demonstrate that the antiferromagnetic moment vector can be stabilized along unique crystallographic directions ([110] and [-110]) under compressive and tensile strains. A direct coupling between the anisotropic antiferrodistortive rotations and the Dzyaloshinskii-Moria interactions drives the stabilization of the weak ferromagnetism. Furthermore, energetically competing C- and G-type magnetic orderings are observed at high compressive strains, suggesting that it may be possible to switch the weak ferromagnetism "on" and "off" under the application of strain. These findings emphasize the importance of strain and antiferrodistortive rotations as routes to enhancing induced weak ferromagnetism in multiferroic oxides.
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN 37830, USA.
authors.forename: Hemant
authors.initials: H
authors.lastname: Dixit
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN 37830, USA.
authors.forename: Jun Hee
authors.initials: JH
authors.lastname: Lee
authors.affiliation: 1] Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN 37830, USA [2] Center for Nanophase Materials Science, Oak Ridge National Lab, Oak Ridge, TN 37830, USA.
authors.forename: Jaron T
authors.initials: JT
authors.lastname: Krogel
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN 37830, USA.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Okamoto
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN 37830, USA.
authors.forename: Valentino R
authors.initials: VR
authors.lastname: Cooper