Abstract
The structures of Pr0.7Ca0.3MnO3 thin films on LaAlO3 (001) and NdGaO3 (001) substrates were investigated using transmission electron microscopy. These substrates induce a significant compressive strain and a slight tensile strain respectively on the film, and quite different microstructures were found in the two cases. Many complex tangles of dislocations were found in the film on LaAlO3, and it had a two-domain structure where both domains have a [110] axis perpendicular to the film plane. The film on NdGaO3 was mostly defect free, apart from occasional precipitates, which appeared to be NaCl-structure MnO, and displayed a single domain structure with the [001] axis perpendicular to the film. The difference in domain structure was explained on the grounds of misfit minimization, and the possible consequences of such a dependence of the domain structure on the substrate for the magnetic properties were discussed.