Thermoelectric size effect in noble metals

Abstract

The difference between the thermoelectric power of thin foils ranging in size from 2.54\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}2}$ to 1.52\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}3}$ mm and a 0.254-mm wire of gold, copper, and silver was measured as a function of temperature from 4.2 to 333\ifmmode^\circ\else\textdegree\fi{}K. The electrical resistance of the wire and the foils was measured at 4.2, 77.3, and 296\ifmmode^\circ\else\textdegree\fi{}K. From the high-temperature results values were obtained for ${[\frac{\ensuremath{\partial}\mathrm{ln}l(\ensuremath{\epsilon})}{\ensuremath{\partial}\mathrm{ln}\ensuremath{\epsilon}}]}_{{\ensuremath{\epsilon}}_{F}}$ and ${[\frac{\ensuremath{\partial}\mathrm{ln}A(\ensuremath{\epsilon})}{\mathrm{ln}\ensuremath{\epsilon}}]}_{{\ensuremath{\epsilon}}_{F}}$ of - 0.58 \ifmmode\pm\else\textpm\fi{} 0.08 and - 1.00\ifmmode\pm\else\textpm\fi{}0.08 for gold, -0.34\ifmmode\pm\else\textpm\fi{}0.11 and -1.20\ifmmode\pm\else\textpm\fi{}0.11 for copper, and +0.86\ifmmode\pm\else\textpm\fi{}0.09 and -1.91\ifmmode\pm\else\textpm\fi{}0.09 for silver, respectively. Analysis of the low-temperature results suggest that the thermoelectric size effect can be used to determine subparts per million concentrations of magnetic impurities in the noble metals.