Nanolamellar magnetoelectric BaTiO3–CoFe2O4 bicrystal

Here, we report a spontaneously formed nanolamellar BaTiO3–CoFe2O4 bicrystal. 11̄0 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 r −1d r /dH 10−2. Since the material can be produced by standard ceramic processing methods, the discovery represents great potential for magnetoelectric devices. © 2009 American Institute of Physics. doi:10.1063/1.3241999