Phase stability and B-site ordering in La2NiMnO6 thin films.

Thin films of multiferroic double-perovskite La2NiMnO6 are prepared on (001)-oriented SrTiO3, (La0.289Sr0.712)(Al0.633Ta0.356)O3, and LaSrAlO4 substrates by pulsed laser deposition. Microstructure investigation by advanced electron microscopy shows that the La2NiMnO6 films have a monoclinic structure on the SrTiO3 substrates and a rhombohedral structure on the (La0.289Sr0.712)(Al0.633Ta0.356)O3 and LaSrAlO4 substrates. Atomic-scale elemental maps of the monoclinic and rhombohedral phases reveal a short-range and/or partial ordering of the B-sites. In addition, domains and columnar grains are found in the films. Our results demonstrate that the phase and microstructure of the La2NiMnO6 films can be tuned by epitaxial strains induced by different substrates. [ABSTRACT FROM AUTHOR]