Nanolamellar magnetoelectric BaTiO3-CoFe2O4 bicrystal

Here, we report a spontaneously formed nanolamellar BaTiO3-CoFe2O4 bicrystal. (1 (1) over bar0) interfaces join the BaTiO3 and CoFe2O4 single crystalline periodically arranged lamellae that have a common [111] direction. The superlattice of approximately 2 nm wavelength is magnetoelectric with a frequency dependent coupling coefficient of 20 mV/Oe cm at 100 Hz. The BaTiO3 component is a ferroelectric relaxor with a Vogel-Fulcher temperature of 311 K. The relaxor behavior gives rise to a magnetic tunability of the relative dielectric constant <epsilon(r)>(-1)d epsilon(r)/dH approximate to 10(-2). Since the material can be produced by standard ceramic processing methods, the discovery represents great potential for magnetoelectric devices. (C) 2009 American Institute of Physics. [doi:10.1063/1.3241999]