We investigate current-perpendicular-plane giant magnetoresistance (CPP-GMR) and current-induced magnetization switching in single-crystalline Fe/Ag/Fe nanopillars of 70 nm diameter. The interplay between the in-plane, fourfold magnetocrystalline anisotropy of the Fe(001) layers and the spin-transfer torque (STT) gives rise to a two-step switching behavior, which allows an investigation of the angular dependences of CPP-GMR and spin-transfer torque. Both behave asymmetrically with respect to the perpendicular alignment of the two Fe layer magnetizations as theoretically predicted due to strong spin accumulation at the Fe/Ag(001) interfaces [M. D. Stiles and D. R. Penn, Phys. Rev. B 61, 3200 (2000)]. The asymmetry parameter determined from the STT data quantitatively agrees with calculated spin-dependent interface resistances, whereas CPP-GMR yields a smaller degree of asymmetry.
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机译：我们研究直径为70 nm的单晶Fe / Ag / Fe纳米柱中的电流垂直平面巨磁电阻（CPP-GMR）和电流感应的磁化转换。 Fe（001）层的面内四重磁晶各向异性与自旋传递扭矩（STT）之间的相互作用产生了两步切换行为，从而可以研究CPP-GMR和自旋转移扭矩。由于在Fe / Ag（001）界面上有很强的自旋积累，因此，两者都相对于两个Fe层磁化的垂直排列不对称，这在理论上是预测的。 D. Stiles和D.R. Penn，物理学B 61，3200（2000）。从STT数据确定的不对称参数在数量上与计算的自旋相关的界面电阻一致，而CPP-GMR产生的不对称程度较小。
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