NMR, Magnetic Susceptibility and Electronic Specific Heat of Nb and Mo Metals and Nb-Tc and Nb-Mo Alloys

Abstract

Magnetic susceptibility and nuclear magnetic resonance measurements have been made in Nb-Tc alloys. Calculations on the temperature variations of electronic specific heats and magnetic susceptibilities are performed for Nb and Mo metals and Nb-Mo alloys by making use of the density of states determined from low temperature specific heat data for 4 d transition metals and their alloys. Temperature variations of the electronic specific heats for Nb and Mo metals are well explained by the present numerical calculations. Temperature variations of the magnetic susceptibilities of these metals and their alloys are explained by taking account of the effect of the temperature independent orbital paramagnetism and the effects of the negative (for Nb metal) and the positive (for Nb 0.75 Mo 0.25 alloy) molecular fields. The Knight shifts of Nb 93 and Tc 99 in Nb-Tc and Nb-Mo alloys are discussed. It is shown that the main contribution to these Knight shifts appear to arise from the orbital paramagnetism of the d electrons.