DHVA OSCILLATIONS AND HIGH-FIELD MAGNETORESISTANCE IN U2RH3SI5

We have observed dHvA oscillations (where H parallel to a'-axis) in a single crystal of U2Rh3Si5 below 1 K. The effective masses an found to be 5.3m(o) and 6.3m(o) for alpha and beta branches, respectively. Lar ge positive magnetoresistances are observed along the a', b- and c-axi s with hystereses above 14.5 T, where the metamagnetic transition is o bserved along b in an earlier study. The low values of effective masse s suggest a local moment on U and a postive magnetoresistance is consi stent with antiferromagnetic ordering in this system. (C) 1998 Elsevie r Science B.V. All rights reserved.