Structural and Magnetic Properties of Co sub(2)MnSi Thin Film with a Low Damping Constant

Co sub(2)MnSi thin films are made by magnetron sputtering onto MgO (001) substrates. The crystalline quality is improved by increasing depositing temperature and/or annealing temperature. The sample deposited at 550[degrees]C and subsequently annealed at 550[degrees]C (sample I) exhibits a pseudo-epitaxial growth with partially ordered L2 sub(1) phase. Sample I shows a four-fold magnetic anisotropy, in addition to a relatively weak uniaxial anisotropy. The Gilbert damping factor of sample I is smaller than 0.001, much smaller than reported ones. The possible reasons responsible for the small Gilbert damping factor are discussed, including weak spin-orbit coupling, small density of states at Fermi level, and so on.