title: Electrically controllable spontaneous magnetism in nanoscale mixed phase multiferroics.
abstract: Magnetoelectrics and multiferroics present exciting opportunities for electric-field control of magnetism. However, there are few room-temperature ferromagnetic-ferroelectrics. Among the various types of multiferroics the bismuth ferrite system has received much attention primarily because both the ferroelectric and the antiferromagnetic orders are quite robust at room temperature. Here we demonstrate the emergence of an enhanced spontaneous magnetization in a strain-driven rhombohedral and super-tetragonal mixed phase of BiFeO₃. Using X-ray magnetic circular dichroism-based photoemission electron microscopy coupled with macroscopic magnetic measurements, we find that the spontaneous magnetization of the rhombohedral phase is significantly enhanced above the canted antiferromagnetic moment in the bulk phase, as a consequence of a piezomagnetic coupling to the adjacent tetragonal-like phase and the epitaxial constraint. Reversible electric-field control and manipulation of this magnetic moment at room temperature is also shown.
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA. midt@berkeley.edu
authors.forename: Q
authors.initials: Q
authors.lastname: He
authors.forename: Y-H
authors.initials: YH
authors.lastname: Chu
authors.forename: J T
authors.initials: JT
authors.lastname: Heron
authors.forename: S Y
authors.initials: SY
authors.lastname: Yang
authors.forename: W I
authors.initials: WI
authors.lastname: Liang
authors.forename: C Y
authors.initials: CY
authors.lastname: Kuo
authors.forename: H J
authors.initials: HJ
authors.lastname: Lin
authors.forename: P
authors.initials: P
authors.lastname: Yu
authors.forename: C W
authors.initials: CW
authors.lastname: Liang
authors.forename: R J
authors.initials: RJ
authors.lastname: Zeches
authors.forename: W C
authors.initials: WC
authors.lastname: Kuo
authors.forename: J Y
authors.initials: JY
authors.lastname: Juang
authors.forename: C T
authors.initials: CT
authors.lastname: Chen
authors.forename: E
authors.initials: E
authors.lastname: Arenholz
authors.forename: A
authors.initials: A
authors.lastname: Scholl
authors.forename: R
authors.initials: R
authors.lastname: Ramesh
mesh_terms: D001729:Bismuth / Q000737:chemistry; D004560:Electricity; D055590:Electromagnetic Phenomena; D004577:Electron Probe Microanalysis; D005290:Ferric Compounds / Q000737:chemistry; D008280:Magnetics; D058185:Magnetite Nanoparticles; D008422:Materials Testing; D013696:Temperature
chemical_list: D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C001215:ferrite; C000499:ferric oxide; D001729:Bismuth