Magnetic Susceptibility and Electronic Specific Heat of Transition Metals and Alloys III. Ni Metal and Ni-Cu Alloys

Abstract

Electronic Specific heat of Ni metal is deduced from the experimental data. It is shown that above the Curie temperature the electronic specific heat coefficient decreases with temperature. The density of electronic states for Ni metal and Ni–Cu alloys is determined as a function of energy from the low temperature specific heat data of Ni and Cu metals and Ni–Fe and Ni–Cu alloys on the basis of the rigid band model. The temperature variations of electronic specific heat and spin paramagnetic susceptibility of paramagnetic Ni metal are calculated. The calculated result on electronic specific heat agrees with experimental result. Whereas the calculated result on spin paramagnetic susceptibility is considerably smaller than the observed susceptibilities. The difference is attributed to the effect of the molecular field and the orbital paramagnetism. Similar calculations are performed for Ni–Cu alloys. The fact that magnetic susceptibilities of Ni–Cu alloys with less than 20 at. % Ni increase with temperature is also accounted for by the band scheme. The molecular field coefficients and the sum of the temperature independent orbital paramagnetic and diamagnetic susceptibilities for these alloys are estimated at several Ni concentrations.