Positive giant magnetoresistance in antiferromagnetic RE(2)Ni(3)Si(5) (RE=Tb, Sm, Nd)

Abstract

Positive giant magnetoresistance (GMR), Delta rho/rho, is reported here in polycrystalline antiferromagnetic materials RE(2)Ni(3)Si(5) (RE=Tb, Sm, Nd); Delta rho/rho, at 4.4 K and in a field of 45 kOe, is 85%, 75%, and 58%, respectively. Positive GMR of such large magnitude has not been reported earlier in magnetically ordered polycrystalline compounds. The observed GMR is not correlated to the RE-moments. It is, however, associated with the magnetic ordering of the lattice as its magnitude is significantly reduced in the paramagnetic state. Surprisingly, MR in Y2Ni3Si5, a non-magnetic rare earth analogue, is also relatively large (16% at 4.4 K; 45 kOe) and is even slightly higher than that of antiferromagnetically ordered Gd2Ni3Si5 (12% at 4.4 K; 45 kOe). The layered structure of the materials is suggested to be responsible for the observed GMR. (C) 1996