Electronic structure of the Ni-Pd-P and Ni-Pt-P metallic glasses: A pulsed NMR study

A pulsed NMR and magnetic susceptibility study of the electronic structure is reported for the rapidly quenched metallic glass systems: (Ni0.50Pd0.50)_100-xPₓ (where 16x26.5), (NiyPd_1-y)₈₀P₂₀ (where 0.20y0.80), and (NiyPt_1-y)₇₅P₂₅ (where 0.20y0.68). The ³¹P Knight shift and nuclear spin-lattice relaxation rate in all three systems depend only on the P concentration, x, and not the Ni concentration, y, nor whether the second transition metal is Pd or Pt. Both the shift and relaxation rate for ³¹P are attributed solely to the direct contact hyperfine interaction. The ¹⁹⁵Pt Knight shift and magnetic susceptibility for (NiyPt_1-y)₇₅P₂₅ do depend on both the Ni concentration and temperature, enabling a determination of the contributions to the shift arising from the direct contact hyperfine and core polarization interactions. The results are discussed in terms of a rigid two-band picture with estimates being made for the s- and d-band densities of states and hyperfine coupling constants. There is strong evidence for a transfer of charge from the P metalloid atoms (M) to the d states of the transition-metal atoms (T), which is consistent with the dense random packing model for T_100-xMₓ metallic glasses.