Temperature dependent phenomena in La1−xSrxMnO3 films studied by magnetic force microscopy

Magnetic domain structure of La1−xSrxMnO3 films was studied using magnetic force microscopy (MFM). Evolution of the magnetic patterns was monitored as a function of temperature by using a variable temperature sample stage. The magnetic contrast in the MFM images decreases as the temperature is raised and vanishes as the system approaches the Tc of the film. At temperatures above the Tc of the film, local ferromagnetic regions with a higher Tc are detected around the grain boundaries. We attribute this variation in the local Tc to the local variation of strain in the film.