Department of Materials Science, Cambridge University, Pembroke Street, Cambridge CB2 3QZ, United Kingdom.
Phys Rev Lett. 2009 Dec 4;103(23):237203. doi: 10.1103/PhysRevLett.103.237203.
Giant magnetoresistance (GMR) arises from differential scattering of the majority and minority spin electrons by a ferromagnet (FM) so that the resistance of a heterostructure depends on the relative magnetic orientation of the FM layers within it separated by nonmagnetic spacers. Here, we show that highly nonequilibrium spin accumulation in metallic heterostructures results in a current-dependent nonlinear GMR which is not predicted within the present understanding of GMR. The behavior can be explained by allowing the scattering asymmetries in an ultrathin FM layer to be current dependent.
巨磁电阻（GMR）源于多数自旋电子和少数自旋电子通过铁磁体（FM）的不同散射，使得异质结构的电阻取决于其中铁磁层的相对磁取向，它们之间由非磁性间隔物隔开。在这里，我们表明金属异质结构中高度非平衡的自旋积累导致了电流相关的非线性 GMR，这在当前对 GMR 的理解中是无法预测的。这种行为可以通过允许超薄膜铁磁层中的散射不对称性随电流变化来解释。
