Magnetoresistance of SmMn2Ge2: A layered antiferromagnet.

Abstract

The behavior of the magnetoresistance in ${\mathrm{SmMn}}_{2}$${\mathrm{Ge}}_{2}$--a layered intermetallic compound--is analogous to the giant magnetoresistance recently reported for artificial metallic multilayers. A moderate magnetic field (2--15 kOe) is sufficient to switch ${\mathrm{SmMn}}_{2}$${\mathrm{Ge}}_{2}$ from the antiferromagnetic (metamagnetic) state to saturation, at a temperature of \ensuremath{\sim}100 K, and this results in a resistance change of 4--8 %. The study of spin-dependent scattering in this and similar layered structures, in which nature has conspired to make essentially perfect interfaces, serves as a complement to the study of the artificial structures.