TRANSPORT AND MAGNETOTRANSPORT PROPERTIES OF U2NI2SN

We report the results of measurements of the magnetoresistance (Delta rho/rho), thermopower (S) and magneto-thermopower (Delta S) for antife rromagnetic U2Ni2Sn (T-N = 25 K), from 3.7 to 100 K and in magnetic fi elds up to 1 T. Critical spin fluctuation effects are observed in d rh o/dT, dS/dT, Delta rho/rho and S. Large negative thermopower values oc cur below similar to 0.8T(N) (and also a sharp decrease of rho), resem bling a spin fluctuation resonance process. However, both Delta rho/rh o and Delta S are positive, which is anomalous in this model.