Fourfold symmetric anisotropic magnetoresistance basedrnon magnetocrystalline anisotropy and antiphase boundariesrnin reactive sputtered epitaxial Fe3O4 films

摘要

The fourfold symmetric anisotropic magnetoresistance u0001AMRu0002 at high fields in epitaxial Fe3O4rnfilms, which is incompatible with the traditional twofold symmetry, was found to be independentrnwith the current direction but associated with their magnetocrystalline anisotropy. u0001001u0002-, u0001110u0002-, andrnu0001112u0002-oriented Fe3O4 films show fourfold symmetry in AMR while twofold symmetry appears forrnu0001111u0002-oriented Fe3O4 films. The cubic magnetocrystalline anisotropy field superimposed onto thernexternal magnetic field modifies the alignment of the spins near antiphase boundaries, leading to thernoscillating scattering rate for the transport electrons across antiphase boundaries and thus therncorresponding fourfold symmetry in AMR.