Magnetic Domain Structure of MnAs Thin Films as a Function of Temperature

We have investigated magnetic domain structures of MnAs thin films grown on GaAs substrates by a magnetic force microscope. Weobserved, by an atomic force microscope, rectangular defects along GaAs [110] direction which disperse randomly on the surface of MnAs/GaAs (001). The Curie temperature of MnAs is 45 C, and it is successfully confirmed directly by the variable temperature magnetic forcemicroscope observation. We also investigated magnetic domain structures of MnAs/GaAs (111)B, and no apparent relation was observedbetween the topographic structure and the magnetic domain structure.(Received July 16, 2003; Accepted September 25, 2003)Keywords: MnAs, magnetic force microscopy, phase transition