Induced ferromagnetism and magnetoelectric coupling in ion-beam synthesized BiFeO3-CoFe2O4 nanocomposite thin films

© 2016 IOP Publishing Ltd. Ferrimagnetic CoFe2O4(cobalt ferrite) is formed within an epitaxial BiFeO3(bismuth ferrite) thin film matrix by Co channeled ion implantation and subsequent annealing. The presence of nanoscale CoFe2O4crystals in the matrix is confirmed by x-ray diffraction using synchrotron radiation. The significantly increased magnetic moment and the low-temperature coercive field of the composite system evidence the formation of ferrimagnetic cobalt ferrite and its nanoscale character, respectively. The results demonstrate that ion beam synthesis is an appropriate method to controllably transform a planar system into a granular one, increasing the interface area between cobalt ferrite and bismuth ferrite. The ferroelectric nature of the BiFeO3-CoFe2O4composite is confirmed by several scanning probe microscopy techniques. At room temperature, the composite exhibits a magnetoelectric voltage coefficient of αME= 17.5 V (cm • Oe)-1, while a single-phase BiFeO3thin film shows a αMEvalue of 4.2 V (cm • Oe)-1. The high magnetoelectric voltage coefficient is interpreted to be the result of the interfacial interaction between the ferrimagnetic CoFe2O4nanocrystallites and the multiferroic BiFeO3matrix.journal_title: Journal of Physics D: Applied Physics article_type: paper article_title: Induced ferromagnetism and magnetoelectric coupling in ion-beam synthesized BiFeO –CoFe O nanocomposite thin films copyright_information: © 2016 IOP Publishing Ltd date_received: 2016-01-20 date_accepted: 2016-06-28 date_epub: 2016-07-21status: publishe