POSSIBLE ABNORMAL MECHANISM FOR LATTICE STRAIN RELAXATION IN La0.7Ca0.3MnO3 THIN FILM

Abstract

La 0.7 Ca 0.3 MnO 3(LCMO) thin films with the thickness of 50 nm were deposited on (001)-oriented single crystal SrTiO 3(STO), MgO and α- Al 2 O 3(ALO) by 90° off-axis radio frequency magnetron sputtering. Grazing incidence X-ray diffraction technique, associated with normal X-ray diffraction, was performed to measure the in-plane lattice parameter and investigate the lattice strain and strain relaxation in LCMO films. The results indicated that critical thickness of strain relaxation is very small, which may be related to large mismatch between film and substrate. The mechanism for strain relaxation in LCMO film is perhaps different from that for tetragonal distortion.