Giant magnetoresistance in actinide systems

In contrast to ferromagnetic uranium intermetallics, which exhibit a large drop below the ordering temperature, the resistivities of uranium antiferromagnets stay at much larger values below T/sub N/. In this contribution, we demonstrate that a large portion of the residual resistance of uranium antiferromagnets can be removed by driving the compounds through metamagnetic transition to a field-aligned state. The consequence is the field-induced drop of resistance, which can exceed /spl Delta//spl rho///spl rho/(0T)=90%.<>