LARGE LOW-TEMPERATURE MAGNETORESISTANCE IN WEAKLY SPIN-CORRELATED CECU2SN2 AND CENI2SN2

Large negative magnetoresistance, Delta R(B)/R(0), of weak Kondo-like systems, CeCu2Sn2 and CeNi2Sn2, was observed in the vicinity of 2 K. A t 8.3 T, it reached 7% and 23% for the former and latter materials, re spectively. The measurements were taken up to 28 K where the magnetore sistance has diminished even at the highest magnetic fields used in ou r study. The results were interpreted in terms of relatively weak mole cular fields which correlate the spin sublattice of these materials. F ollowing the approach proposed by Abrikosov for calculating resistivit y in weakly spin-correlated Kondo-like systems, we were able to fit su ccessfully all our results. The fitting produced an estimate of the sp in exchange integral for electron-impurity interaction J, which was fo und to be of the order of 0.36 meV for both systems.