MAGNETORESISTANCE, HALL-EFFECT, AND THERMOELECTRIC-POWER IN SPIN VALVES

Comparison of the magnetoresistance (MR) on two groups of spin-valve m ultilayers, NiO/NiFe/ Cu/NiFe/Cu/NiO and NiO/NiFe/Cu/NiFe/Cu, has been made in order to investigate the possibility of the enhanced specular scattering at NiO/metal interface. No clear difference in MR between the two systems has been found, suggesting that the enhancement of spe cular scattering at interfaces is not the origin of the large MR. For the held direction almost perpendicular to the plane, we found a sensi tive angular dependence of MR along with a large unidirectional anisot ropy. To sort out any specific characteristics of the spin-valve syste m compared to the multilayers, thermoelectric power and Hall effect ha ve been investigated for the first time. (C) 1998 American Institute o f Physics. [S0021-8979(98)07411-8].