Large low-temperature magnetoresistance in weakly spin-correlated CeCu2Sn2 and CeNi2Sn2

Large negative magnetoresistance, ΔR(B)/R(0), of weak Kondo-like systems, CeCu2Sn2 and CeNi2Sn2, was observed in the vicinity of 2 K. At 8.3 T, it reached 7% and 23% for the former and latter materials, respectively. The measurements were taken up to 28 K where the magnetoresistance has diminished even at the highest magnetic fields used in our study. The results were interpreted in terms of relatively weak molecular fields which correlate the spin sublattice of these materials. Following the approach proposed by Abrikosov for calculating resistivity in weakly spin-correlated Kondo-like systems, we were able to fit successfully all our results. The fitting produced an estimate of the spin exchange integral for electron-impurity interaction J, which was found to be of the order of 0.36 meV for both systems.