The magnetization $\left(M\right)$ of a ${\text{LaCoO}}_3$ film grown epitaxially on a piezoelectric substrate has been investigated in dependence on the biaxial in-plane strain. $M$ decreases with the reversible release of tensile strain, with a maximum change of at least 6% per 0.1% of biaxial strain near the Curie temperature $\left(T_C\right)$. The biaxial strain response of $T_C$ is estimated to be below 5 K/% in the tensile strain state. This is in agreement with results from statically strained films on various substrates. As possible origins of the strain-induced magnetization are considered (i) the strain-dependent Curie temperature, (ii) a strain-dependent magnetically inhomogeneous (phase-separated) state, and (iii) a strain-dependent magnetic moment (spin state) of Co ions. The $T_C$ shift is found insufficient to explain the measured strain-induced magnetization change but contributions from mechanism (ii) or (iii) must be involved.

• Received 29 May 2008

DOI:https://doi.org/10.1103/PhysRevB.79.092409