Domain structures of BaTiO3 in epitaxial BaTiO3/(NiFe2O4/BaTiO3)m/SrTiO3 multilayer films

BaTiO3/(NiFe2O4/BaTiO3)(m)/SrTiO3 (m = 1, 2, 3, 4) epitaxial heterostructures were fabricated on (0 0 1)-SrTiO3 substrates by employing the pulsed-laser deposition technique. Crystallographic characteristics of these multilayered composite films such as lattice constants, c/a ratio of tetragonal unit cell and the fraction of c-domain with the c-axis of the tetragonal unit cell parallel to the substrate normal direction or degree of c-axis orientation were evaluated. The coexistence of c-and a-domains with the c-axis of the tetragonal unit cell perpendicular to the substrate normal direction in these heterostructures was verified by the {3 0 3} asymmetric rocking curve measurement.