Artificially controlled magnetic domain structures in ferromagnetic dots/ferroelectric heterostructures

A variation in the magnetization and magnetic domain structures of epitaxial Fe dots on a single crystal BaTiO(3) substrate is demonstrated in association with the structural phase transition of ferroelectric BaTiO(3). The temperature dependent magnetization of Fe dots drops suddenly at 282 K and increases again at 189 K with decreasing temperature. The variations clearly correspond to the successive structural phase transitions of BaTiO(3) from tetragonal to orthorhombic phases and from orthorhombic to rhombohedral phases. After a thermal cycle between room temperature and 150 K passing through these phase transitions, the initial magnetic domain structure of Fe dots with an enclosed magnetic flux structure changes to a single-domain-like structure due to interfacial strain between Fe and BaTiO(3) arising from possible switching of c-axis orientation of BaTiO(3) substrate. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3054357]