The spin density in ${\mathrm{Co}}_2\mathrm{FeGa}$ Heusler alloy has been measured in a magnetic Compton scattering experiment using 274-keV circularly polarized synchrotron radiation at the high energy inelastic scattering beamline (BL08W) at SPring-8, Japan. A detailed band-structure calculation including hyperfine field study was performed utilizing the generalized gradient corrected full-potential linear augmented plane-wave (FLAPW-GGA) method. The magnetic Compton profiles for the [100], [110], and [111] principal directions, reported here, show anisotropy in the momentum density which is in good agreement with the FLAPW-GGA results based on ferromagnetic ground state. The conduction electrons were found to have a negative spin polarization of $0.60{\mu }_B,$ which is at variance with the prediction of a positive moment from the recent neutron data. In the calculation, $3d$ spin moment at the Co and Fe site was found to be $1.20{\mu }_B$ and $2.66{\mu }_B,$ and their respective contribution in the $e_g$ and $t_{2g}$ sub-bands are in excellent agreement with the earlier reported neutron-diffraction measurements. It is also seen from our calculated results that the Co and Fe moment are mainly $e_g$ in character.

• Received 10 July 2000

DOI:https://doi.org/10.1103/PhysRevB.63.064409