Superconductivity and the electronic structure of Zr- and Hf-based metallic glasses

Abstract

The results of a comprehensive study of the superconducting transition temperatures of Zrand Hf-based metallic glasses are reported. The microscopic origins of superconductivity in these glasses are discussed in terms of recent ultraviolet photoelectron spectroscopy (UPS) measurements and calculations based on the renormalized atom technique. These calculations accurately predict the UPS spectra and the results of low-temperature heatcapacity measurements.The complete description of the electronic structure afforded by these calculations allows, for the first time, a consistent picture of the variation of T, with X in the glasses Zr~» X» (X=3d or 4d transition metals). In addition, the dependence of T, with composition (y) can be understood in terms of the X d subband positions relative to E~. The results reported here support our recent contention that the strong depression of T, observed for X=Fe, Mn, Cr, and V glasses is related to the formation of localized magnetic moments and spin fluctuations. An alternate explanation for the low T, of X=V and Cr glasses based on the idea of an atomic-structure change is also discussed.

Subsurface miscibility of metal overlayers with V, Nb and Ta substrates

“…Jarlborg et al [79] showed that in the A 3 B 1 alloys (A = V, Nb and B = Ir, Pt, Au) the bottom of the DOS is always determined by the DOS located in the muffin-tin sphere of the B-atom. These are also shifted to larger binding energies compared to the DOS of pure metal B. Pd alloys with various substrates like Sc, Zr, Ti, Y, La, Ce, Pr, Nd, Sm, Th, Ur and Al give only deep lying Pd states [80][81][82]. A similar observation was made for the A 3 B 1 , Zr 3 Rh 1 and Zr 3 Ni [81] alloys.…”

The magnetic susceptibility of hydrogen-doped partially crystalline (Zr76Ni24)1−xHx metallic glasses

“…These metallic glasses are relatively easy to prepare and especially interesting because the low-temperature configuration changes from superconductivity through enhanced paramagnetism to ferromagnetism with increase in 3d transition-metal concentration [1][2][3]. Most of the results have been reported on the rapidly melt-quenched amorphous samples and a few results are available for partially crystalline samples.…”

Structure and crystallization of the partially crystalline Zr76Ni24 metallic glass

“…These metallic glasses are especially interesting due to the low-temperature configuration changes from superconductivity through enhanced paramagnetism to ferromagnetism with increasing 3d concentration [8,9]. Zr-3d metallic glasses are used in a number of applications because of their mechanical properties.…”