NMR of Co59in amorphous CoP alloys

The results of an NMR study on 59 Co in electrodeposited ferromagnetic CoP alloys with P content ranging between 6-23.5 at.% are reported. The concentration dependence of the hyperfine field distribution in as-plated amorphous alloys was examined at zero field. Hyperfine fields are distributed around two main values: the first one (190 kOe) corresponds to Co nuclei unaffected by presence of P; the second one, to 'clusters' of 3 or 4 Co nuclei surrounding a P atom. The effect of structural disorder results in lowering the local field at Co nuclei in amorphous cobalt. The field dependence of the Co 59 resonant frequency in an amorphous sample progressively annealed shows the existence of single domain crystallites in the crystallized state.