Electronic structures of Pd₃₀Pt_17.5Cu_32.5P₂₀ bulk metallic glass

The incident-photon energy, hν, dependence of the valence-band electronic structure was measured by photoemission spectroscopy (PES) on Pd30Pt17.5Cu32.5P20 (PPCP) bulk metallic glass, having a critical-cooling-rate similar to that of the Pd42.5Ni7.5Cu30P20 (PNCP) excellent glass-former. The density of states (DOS) near the Fermi energy is mainly composed of the Pd 4d and Pt 5d electrons. The partial Pd 4d, Pt 5d, and Cu 3d DOSs in the valence band were estimated by the hν dependence of the photo-ionization cross-sections, and a localized tendency was clarified for the Pd 4d electrons. Core-level PES measurements were also carried out at the Pd 3d5/2, Pt 4f7/2, Cu 3p1/2, and P 2p levels. The Pd 3d5/2 core level largely shifts toward the deeper electron energies by replacing Ni with Pt atoms from PNCP, indicating a charge transfer from the P and Pd atoms. The width of the peak becomes wider in PPCP than in PNCP for the Pd 3d5/2 core level, suggesting that local structures around the Pd atoms become heterogeneous or less uniform.