IMPROVED EDDY-CURRENT DECAY METHOD FOR RESISTIVITY CHARACTERIZATION

Eddy-current decay is a unique, nondestructive method for determining the low-temperature resistivity of large samples of pure metal. Furthe rmore, it is the only means available for measurement of the residual resistivity ratio (RRR), rho(273 K)/rho(4 K), of samples with shapes t hat do not lend themselves to conventional four-wire resistance measur ement technique. An improvement to an earlier implementation of the ed dy-current decay method of resistivity characterization is presented. It involves modernizing the earlier apparatus by the use of a digitizi ng oscilloscope, commercial curve-fitting software, digital averaging techniques, and modern electronics. Data are shown for high-purity cop per cylinders.