Stress-induced surface magnetization of (La/sub 0.7/Sr/sub 0.3/)MnO/sub 3/ thin films

The role of stress on magnetic properties of epitaxial (La/sub 0.7/Sr/sub 0.3/)MnO/sub 3/ (LSMO) films has been studied. We have investigated 1100 /spl Aring/ thick LSMO films deposited on LaAlO/sub 3/ (Sample L, under a compressive stress) and SrTiO/sub 3/ (Sample S, under a tensile stress) using magnetic force microscopy (MFM), DC hysteresis loop, and ferromagnetic resonance (FMR) measurements. The magnetic force microscope image of Sample L shows a "maze-like" pattern indicating sizable out-of-plane magnetization, while the magnetic image of Sample S shows a"feather-like" pattern indicative of an in-plane magnetization. The hysteresis loop and ferromagnetic resonance measurements give quantitative evidence for the role of the lattice mismatch between the film and the substrate in the magnetic anisotropy of the two films. Our systematic examination of various thickness LSMO films on LaAlO/sub 3/ reveals that the maze pattern is exhibited only between 500 /spl Aring/ and 1700 /spl Aring/ thick films. Despite larger anisotropy, no maze pattern is observed in films thinner than 360 /spl Aring/.