Abstract Scope |
Ferroelectrically induced weak ferromagnetism had been predicted in compounds MTiO3 (M=Fe,Mn,Ni) with the LiNbO3-type structure. In order to stabilize this metastable structure by oxide heteroepitaxy, we attempted to grow epitaxial NiTiO3 films on Al2O3, Fe2O3, and LiNbO3 substrates by pulsed laser deposition. Given the structural imperfections of the as-deposited films on sapphire substrates arising from the large lattice mismatch, we investigated the effect of post-synthesis annealing on the films’ properties. The crystalline quality of the Ni1-xTi1-yO3/Al2O3 films was greatly improved by post-growth annealing. The effect of the different kind of strain exerted by the different substrates (Al2O3, Fe2O3, LiNbO3) on the resulting electrical and magnetic properties of the films was investigated. LiNbO3 was chosen as the substrate resulting in the best quality films, both structurally and physical property-wise. Finally, ferroelectricity, ferromagnetism, and their magnetoelectric coupling were demonstrated on NiTiO3/LiNbO3 films. |