Observation of magnetic domain behavior in colossal magnetoresistive materials with a magnetic force microscope

Magnetic domain behavior was imaged in calcium-doped lanthanum manganese trioxide films. Magnetic domains behave differently at temperatures that are well below and near the Curie temperature T-c. At low temperatures the domains are very stable. As temperature rises toward T-c, domain-domain interactions become weaker and domains become highly mobile and subject to merging and splitting, yet the domains are still traceable. The contrast (which is a measure of magnetization) and size of domains continuously reduce to zero. The temperature at which the domains disappear agrees with the T-c obtained by a macroscopic magnetization measurement. Sample defects such as scratches lend to attract magnetic domains.