The Spin Dependent Momentum Density of Hexagonal Close Packed Cobalt

Directional-spin-dependent Compton profiles of ferromagnetic hexagonal close packed cobalt metal have been measured with 117 keV and 167 keV circularly polarized synchrotron radiation at the new ESRF high energy beamline. Significantly improved resolution was achieved at the higher energy. The results have been compared with the profile predicted from an augmented plane wave (APW) calculation of the electron momentum density in the hexagonal phase. No significant difference was found between thec-axis and the basal plane magnetic profiles. The experiments show that there is substantially more 3dspin density at high momentum than in the model calculation. After correcting for this deficiency we find that the 4s–pcomponent of the momentum density remains significantly different than predicted.