Magnetic domain structures of La_0.67Sr_0.33MnO₃ thin films with different morphologies

Using a wide-field Kerr microscope, we have studied the magnetic domain structures of epitaxial and polycrystalline La0.67Sr0.33MnO3 thin films as well as a film having thermally induced 〈110〉 microcracks. The epitaxial film on a (001) SrTiO3 substrate has different magnetic domain behaviors for in-plane fields applied along the 〈100〉 and 〈110〉 directions. Magnetic domain orientation and contrast suggest a biaxial magnetic anisotropy with 〈110〉 easy axes. Defects such as microcracks and grain boundaries have a strong perturbing effect on the local magnetization and can lead to an enhanced and controllable spin-dependent scattering. © 1997 American Institute of Physics.