Persistence of the orthorhombic phase in YMnO 3 hexagonal thin films.

YMnO3thin films were prepared based on a chemical solution deposition route. Their structure was studied as a function of the annealing temperature using X-ray diffraction, Raman spectroscopy, and electron backscatter diffraction. For annealing temperatures above 850°C the films, though crystallizing predominantly in aP63cmhexagonal structure, exhibit a thin Pnma orthorhombic phase close to the film-substrate interface. It is shown that the residual orthorhombic structure is associated with a substrate induced strain state, characterized by an expansion in the in-planeadirection, and a compression in the out of plaincdirection. [ABSTRACT FROM PUBLISHER]