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: ${\left({\mathrm{Ni}}_{0.50}{\mathrm{Pd}}_{0.50}\right)}_{100-x}{\mathrm{P}}_x$ (where $16\leqq x\leqq 26.5$), ${\left({\mathrm{Ni}}_y{\mathrm{Pd}}_{1-y}\right)}_{80}{\mathrm{P}}_{20}$ (where $0.20\leqq y\leqq 0.80$), and ${\left({\mathrm{Ni}}_y{\mathrm{Pt}}_{1-y}\right)}_{75}{\mathrm{P}}_{25}$ (where $0.20\leqq y\leqq 0.68$). The ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$ 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 ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$ are attributed solely to the direct contact hyperfine interaction. The ${}_{}{}^{195}{}_{}{}^{}\mathrm{Pt}$ Knight shift and magnetic susceptibility for ${\left({\mathrm{Ni}}_y{\mathrm{Pt}}_{1-y}\right)}_{75}{\mathrm{P}}_{25}$ 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 $T_{100-x}{M}_x$ metallic glasses.