High-sensitivity resistivity technique for studies of defect behavior

An experimental method for measurement of the contribution to the electrical resistivity due to solutes or defects is described. This technique, which is based on an ac Kelvin Double Bridge may be used at elevated temperatures and does not require the use of liquid helium. The resistivity caused by solutes or defects, rho/sub x/s, can be determined at temperatures near 300 K with an accuracy of better than δrho/sub x/s/rho/sub x/sroughly-equal10-3; with the major source of error being the accuracy to which the material resistivity is known. Relative changes in the solute (defect) resistivity can be measured with a precision of 5 x 10-10 Ω cm. A specimen design and mounting procedure, which takes advantage of the high bridge sensitivity, is described