Electronic structure of bulk metallic glass Zr55Al10Cu30Ni5

Full text: The electronic structure of a bulk metallic glass Z55Al10Cu30Ni5 has been studied by means of photoelectron spectroscopy in order to understand the origins of its large glass formation ability and unique mechanical properties from the microscopic point of view. Photoelectron spectra were recorded at low temperatures with a high-resolution analyzer at BL5U of UVSOR, a 750 MeV electron storage ring at Institute for Molecular Science. Specimens were cut from an ingot of the metallic glass prepared by a casting method and their clean surfaces for the photoelectron measurement were obtained by in situ scraping the specimen with a diamond file. The valence-band photoelectron spectra show three bands ascribed to the Zr 4d, Ni 3d and Cu 3d states. Remarkable feature of these bands is the highly-symmetric spectral shape with the high binding energy and narrow width in comparison with the d bands of the crystalline transition metals. This is attributed to the reduction in the neighboring atoms to hybridize with those transition metals and the lack of the crystalline periodicity in the metallic glass. High-resolution measurement also reveals the intensity reduction near the Fermi level, which implies the pseudo-gap in the electronic structure may be one of the important factors for the glass formation