Specific Heat and Electrical Resistivity of Exchange-Enhanced DilutePt-Ni Alloys

Abstract

Experimental measurements of the specific heat and electrical resistivity of dilute $\mathrm{Pt}$-Ni alloys have been made at temperatures from ∼1.2 to 4.2°K. Specimen compositions were 1.0-, 3.4-, 7.7-, and ${12.8}_5$-at.%Ni for the specific-heat work and 0.67-, 1.3-, 2.0-, 4.0-, and 9.4-at.%Ni for the resistivity work. The specificheat data for each alloy are well fitted by a relation of the form $C=\gamma T+{\beta }^{\prime }{T}^3$, the resistivity data by a relation of the form $\rho ={\rho }_0+A{T}^2$. The dependence of $\gamma$, ${\beta }^{\prime }$, and $A$ upon the Ni concentration $c$ may be expressed as follows: $\frac{{\gamma }^{-1\mathrm{}}d\gamma }{\mathrm{dc}}\simeq 3$ over the entire range of composition investigated; for the lower concentrations only, $\left(\frac{1}{{\beta }^{\prime }}\right)\left(\frac{d{\beta }^{\prime }}{\mathrm{dc}}\right)\sim -3\mathrm{} \mathrm{to} -7\mathrm{}$ and $\frac{A^{-1\mathrm{}}\mathrm{dA}}{\mathrm{dc}}\simeq 28$. The experimental results are used to evaluate current theories of localized spin-fluctuation effects; qualitative agreement is good, although quantitative agreement is very limited.