Liquid Phase Synthesis and Morphological Observation of BaTiO₃-CoFe₂O₄ Nanocomposite Films.

A novel and inexpensive fabrication method of multiferroic nanocomposite films via liquid-phase formation is demonstrated in this work. Well-aligned anodized TiO₂ nanotube arrays on a Ti substrate were used as the core template. The anodized TiO₂ nanotube arrays were then hydrothermally treated in Ba(OH)₂ aqueous solution to form BaTiO₃ (BTO) nanotube arrays. The average pore diameter and thickness of the BTO nanotube arrays obtained were approximately 50~70 nm and 2~4 m, respectively. The BTO nanotube arrays were then dip-coated with CoFe₂O₄ (CFO) sol with the assistance of vaccum impregnation equipment to enable the penetration of CFO sol into the tubular pores of the BTO nanotube arrays. The good distribution of CFO in the BTO nanotube arrays was confirmed by electron microscopy accompanied with elemental analysis. The good crystallinity of CFO and BTO in the nanocomposite was confirmed by X-ray diffraction, and the nanocomposite film exhibited anisotropic ferrimagnetic properties upon an in plane and out-plane applied magnetic field.