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 magn eto-optical Kerr effect measurements. It is found that the Co-rich and Mn-r ich films exist in body-centered-cubic and face-centered-cubic structures, respectively. Meanwhile, the Co1-xMnx films show ferromagnetism whenever th e structure is bcc, but they show antiferromagnetism or paramagnetism whene ver the structure is fcc. This strong correlation established between the s tructure and magnetism was further studied and confirmed by an ab initio el ectron linearized augmented-plane-wave calculation with the local-spin-dens ity approximation. (C) 2001 American Institute of Physics.