Substrate effect on the magnetic microstructure of La0.7Sr0.3MnO3 thin films studied by magnetic force microscopy

Colossal magnetoresistive La0.7Sr0.3MnO3 thin films have been grown under tensile strains on (100)-SrTiO3 substrates and compressive strains on (100)-LaAlO3 and (110)-NdGaO3 substrates by pulsed laser deposition. Using magnetic force microscopy (MFM), a feather-like magnetic pattern, characteristic of films with an in-plane magnetization, is observed for films deposited on both SrTiO3 and NdGaO3 while a bubble magnetic pattern, typical of films with an out-of-plane magnetization, is recorded for LaAlO3. We show that the shape of the magnetic pattern imaged by MFM is fully correlated to the easy direction of the magnetization in the film. (C) 2001 American Institute of Physics.