Microstructure of Epitaxial La0.7Ca0.3MnO3 Thin Films Deposited by Direct Current Magnetron Sputtering on LaAlO3 Substrate

Transmission electron microscopy (TEM) and high resolution electron microscopy (HREM) have been used to study the microstructural properties of La0.7Ca0.3MnO3 films on (001) LaAlO3 substrates prepared by direct current magnetron sputtering technique. The as-grown thin films with different thickness are perfectly coherent with the substrates. The film suffers a tetragonal deformation in the area near the interface between the-film and the substrate. With increasing thickness, the film is partially relaxed. It was found that La0.7Ca0.3MnO3 films consist of two types of oriented domains described as: (1) (110)(f)[001](f)parallel to(001)(s)[100](s) and (1 (1) over bar0)(f)[001](f)parallel to(001)(s)[100](s) and (2) (110)(f)[001](f)parallel to(001)(s)[010](s) and (1 (1) over bar0)(f)[001](f)//(001)(s)[010](s). Upon annealing, the film is relaxed by the formation of misfit dislocations. Other than misfit dislocations, two types of threading dislocations with Burgers vector of < 100 > and < 110 > were also identified.