title: 100-nm-sized magnetic domain reversal by the magneto-electric effect in self-assembled BiFeO3/CoFe2O4 bilayer films.
abstract: A (001)-epitaxial-BiFeO3/CoFe2O4 bilayer was grown by self-assembly on SrTiO3 (100) substrates by just coating a mixture precursor solution. The thickness ratio of the bilayer could be controlled by adjusting the composition ratio. For example, a BiFeOx:CoFe2Ox = 4:1 (namely Bi4CoFe6Ox) mixture solution could make a total thickness of 110 nm divided into 85-nm-thick BiFeO3 and 25-nm-thick CoFe2O4. Self-assembly of the bilayer occurred because the perovskite BiFeO3 better matched the lattice constant (misfit approximately 1%) and crystal symmetry of the perovskite SrTiO3 than the spinel CoFe2O4 (misfit approximately 7%). The magnetic domains of the hard magnet CoFe2O4 were switched by the polarization change of BiFeO3 due to an applied vertical voltage, and the switched magnetic domain size was approximately 100 nm in diameter. These results suggest that self-assembled BiFeO3/CoFe2O4 bilayers are interesting in voltage driven nonvolatile memory with a low manufacturing cost.
authors.affiliation: Department of Applied Physics, Faculty of Science, Tokyo University of Science, 6-1-3 Niijuku, Katsushika, Tokyo 125-8585, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Sone
authors.affiliation: Department of Applied Physics, Tohoku University, 6-6-05 Aoba, Aramaki, Aoba, Sendai 980-8579, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Naganuma
authors.affiliation: Department of Applied Physics, Faculty of Science, Tokyo University of Science, 6-1-3 Niijuku, Katsushika, Tokyo 125-8585, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Ito
authors.affiliation: Department of Instrumental Analysis, Tohoku University, 6-6-11 Aoba, Aramaki, Aoba, Sendai 980-8579, Japan.
authors.forename: Takamichi
authors.initials: T
authors.lastname: Miyazaki
authors.affiliation: Department of Applied Physics, Faculty of Science, Tokyo University of Science, 6-1-3 Niijuku, Katsushika, Tokyo 125-8585, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakajima
authors.affiliation: Department of Applied Physics, Faculty of Science, Tokyo University of Science, 6-1-3 Niijuku, Katsushika, Tokyo 125-8585, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Okamura
mesh_terms: D001729:Bismuth / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D004560:Electricity; D005296:Ferrous Compounds / Q000737:chemistry*; D008280:Magnetics; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D010087:Oxides / Q000737:chemistry; D013324:Strontium / Q000737:chemistry; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D005296:Ferrous Compounds; D010087:Oxides; D003035:Cobalt; D014025:Titanium; C119252:strontium titanium oxide; D001729:Bismuth; D013324:Strontium