ELECTRONIC-STRUCTURE AND ELECTRON-TRANSPORT PROPERTIES OF AL-BASED (NI-67 TI-33), (NI-67 ZR-33), (NI-67 LA-33) AMORPHOUS-ALLOYS

A large number of (Ni67X33)1-xAl x(X identical to Ti, Zr and La; 0<or=x<or=0.85) ternary amorphous alloys have been synthesised by the melt-spinning technique in combination with the sputtering method as a supplementary tool. The electronic structure was studied through measurements of the low-temperature specific heats and the X-ray photoemission spectroscopy (XPS) spectra. For comparison, the amorphous Al100-x-ySixNiy (10<or=x<or=35, 10<or=y<or=20) alloys were also prepared and their valence band structure was studied by XPS and soft-X-ray spectroscopy. As electron transport properties, the authors measured the electrical resistivity, the Hall coefficient and the thermoelectric power over a wide temperature range below 300 K. They revealed that the electronic structure at the Fermi level changes from the d- to sp-electron-dominant states, as the Al content increases across x=0.6. This drastic change in the electronic structure is found to be reflected in various electron transport properties and the crystallisation temperature. A reversal in the sign of the Hall coefficient and the change in the characteristic feature of the temperature dependence of the electrical resistivity have been discussed in relation to the electronic structure involved.