Structure and magnetism of Co1-xMnx alloys epitaxially grown on GaAs(001)

The structure and magnetism of Co1-xMnx films grown on GaAs(001) substrates were characterized by reflection high energy electron diffraction and magneto-optical Kerr effect measurements. It is found that the Co-rich and Mn-rich films exist in body-centered-cubic and face-centered-cubic structures, respectively. Meanwhile, the Co1-xMnx films show ferromagnetism whenever the structure is bcc, but they show antiferromagnetism or paramagnetism whenever the structure is fcc. This strong correlation established between the structure and magnetism was further studied and confirmed by an ab initio electron linearized augmented-plane-wave calculation with the local-spin-density approximation. (C) 2001 American Institute of Physics.