Specific Heat and Electrical Resistivity of Exchange-Enhanced Dilute<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Pt</mml:mi></mml:math>-Ni Alloys

Abstract

Experimental measurements of the specific heat and electrical resistivity of dilute $\mathrm{Pt}$-Ni alloys have been made at temperatures from \ensuremath{\sim}1.2 to 4.2\ifmmode^\circ\else\textdegree\fi{}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 $C=\ensuremath{\gamma}T+{\ensuremath{\beta}}^{\ensuremath{'}}{T}^{3}$, the resistivity data by a relation of the form $\ensuremath{\rho}={\ensuremath{\rho}}_{0}+A{T}^{2}$. The dependence of $\ensuremath{\gamma}$, ${\ensuremath{\beta}}^{\ensuremath{'}}$, and $A$ upon the Ni concentration $c$ may be expressed as follows: $\frac{{\ensuremath{\gamma}}^{\ensuremath{-}1}d\ensuremath{\gamma}}{\mathrm{dc}}\ensuremath{\simeq}3$ over the entire range of composition investigated; for the lower concentrations only, $(\frac{1}{{\ensuremath{\beta}}^{\ensuremath{'}}})(\frac{d{\ensuremath{\beta}}^{\ensuremath{'}}}{\mathrm{dc}})\ensuremath{\sim}\ensuremath{-}3 \mathrm{to} \ensuremath{-}7$ and $\frac{{A}^{\ensuremath{-}1}\mathrm{dA}}{\mathrm{dc}}\ensuremath{\simeq}28$. The experimental results are used to evaluate current theories of localized spin-fluctuation effects; qualitative agreement is good, although quantitative agreement is very limited.