Magnetic properties of CoFe[sub 2]O[sub 4]-BaTiO[sub 3] composites

The aim of the present work is to study how the volume (lattice parameters) changes of barium titanate, induced by a phase transition, which occurs by temperature sweeps, influence magnetic behavior of cobalt ferrite in their composites via inverse magnetostrictive (Villari) effect. Structure, phase composition, and magnetic properties were investigated using X-ray diffraction, Mössbauer spectroscopy, and temperature dependence of magnetization. The tetragonal-to-orthorhombic phase transition in barium titanate occurring at ∼280 K on cooling can be observed in the zero-field cooled magnetization curve. The other phase transitions, i.e., tetragonal-to-cubic transition at ∼390 K and orthorhombic-to-rhombohedral transition at ∼178 K, were detected neither by magnetic nor by Mössbauer measurements.