Low-Temperature Magnetic Force Microscopy studies of LCMO and LSMO films on BTO substrates*

Strong strain-mediated magnetoelectric coupling arises at epitaxial planar interfaces, e.g. between ferromagnetic films and ferroelastic substrates [1]. Discontinuous changes in strain at the $\sim $190 K rhombohedral-orthorhombic transition of a ferroelastic BaTiO$_{3}$ substrate produce discontinuous changes in the macroscopic magnetizations of ferromagnetic epitaxial thin films of La$_{0.7}$Ca$_{0.3}$MnO$_{3}$ or La$_{0.67}$Sr$_{0.33}$MnO$_{3}$ [1]. In order to explore the microscopic changes through this transition, we will present magnetic force microscopy data for the two systems above and below $\sim $190 K. [1] M. K. Lee \textit{et al.}, \textit{Appl. Phys. Lett.} \textbf{77} (2000) 3547; W. Eerenstein \textit{et al.}, \textit{Nature Materials} \textbf{6} (2007) 348