Nanolamellar magnetoelectric BaTiO_3-CoFe_2O_4 bicrystal

摘要

Here, we report a spontaneously formed nanolamellar BaTiO_3-CoFe_2O_4 bicrystal. (110) interfaces join the BaTiO_3 and CoFe_2O_4 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 BaTiO_3 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 <ε_r>~(-1)dε_r/dH ≈ 10~(-2). Since the material can be produced by standard ceramic processing methods, the discovery represents great potential for magnetoelectric devices.