Strain induced anisotropy in the electronic properties of ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}\mathrm{Mn}{\mathrm{O}}_3$ thin films was investigated by x-ray absorption spectroscopy at the Mn $2p$ and O $1s$ edges. Films on (100) $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ and (100) $\mathrm{La}\mathrm{Al}{\mathrm{O}}_3$ substrates were grown by pulsed laser deposition with in situ reflection high energy electron diffraction diagnostic. At both absorption edges, clear features related to different anisotropic lattice strain effects as a function of the substrate were observed. On the average a negative (positive) linear dichroism was obtained for films grown under in-plane tensile (compressive) epitaxial strain conditions. Indeed, the structural macroscopic distortion induced by the substrate is responsible of the octahedra distortions with the resulting stabilization of $x^2\text{−}{y}^2$ $\left(3z^2\text{−}{r}^2\right)$ orbitals. Enhanced linear dichroism at the Mn $2p$ edge in very thin films, only a few unit cells thick, is in agreement with a fully strained state which favors the formation of orbital ordered phase regions.

• Received 28 February 2006

DOI:https://doi.org/10.1103/PhysRevB.73.235121