Low-temperature specific heat of V-substituted NiZr(V) metallic glass

Abstract

Low-temperature (1.7 ∼ 5.5K) specific heat measurements are reported for four series of seventeen metallic glasses, Ni 100−xZr x (x=50∼75), (Ni .33Zr .67) 100−xV x, (Ni .50Zr .50) 100−xV x and (Ni .67Zr .33) 100−xV x (x=10∼25), in order to study the effect of V (3d metal) substituted for Zr (4d metal) on NiZr metallic glasses in terms of the electronic structure near the Fermi energy E F. Each set of C/T vs T 2 plot has been fitted to the equation C = γ T+ β T 3+ δ T 5 except for the binary alloy, showing the superconducting transition above 1.7 K. It is found that the electronic specific heat coefficient γ increases with increasing V content and the rate of increase Δ γ per V content is also an increasing function of Ni content. The results are attributed to the fact that the height of the electronic density of states at E F almost arising from the early transition metal increases due to the stronger localization of 3d and the new bonding states between Ni and V are enhanced with increasing Ni content. This latter character is consistent with the variation of the short range order parameter of NiZr pairs on Ni content for the same NiZr(V) metallic glasses.