LARGE MAGNETORESISTANCE IN RARE-EARTH BASED ALLOYS

The results of magnetoresistance (Delta rho/rho) measurements at low t emperatures on the alloys, CeIr2B2, Pr(0.2)R(0.8)Cu(2)Ge(2), Pr(0.2)R( 0.8)Ni(2)Si(2), and Pr(0.2)R(0.8)Cu(2)Si(2) (R = La, Y), are reported. The Delta rho/rho of CeIr2B2 at 5 K (in the ferromagnetically ordered state) is large (-60%) at 70 kOe. In the case of Pr alloys, Delta rho /rho is positive thereby proving that the Kondo effect is absent in th ese alloys. One of the Pr alloys, Pr0.2La0.8Cu2Si2, also exhibits a la rge positive Delta rho/rho at 5 and 10 K about (28% at 70 kOe). Releva nce of these findings to the current topic of interest on giant magnet oresistance will be pointed out.