Bipolar high-field excitations in Co/Cu/Co nanopillars
Bipolar high-field excitations in Co/Cu/Co nanopillars
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Co/Cu/Co 纳米柱中的双极高场激发
DOI：
10.1103/physrevb.71.140403
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发表时间：
2004
影响因子：
3.7
通讯作者：
J. Sun
中科院分区：
文献类型：
--
作者：
B. Ozyilmaz;A. Kent;M. Rooks;J. Sun
实验研究了Co/Cu/Co双层纳米柱（直径为50 nm）在低温下垂直于层的大磁场下的电流诱导磁激发。在足够高的电流密度的激励，这导致微分电阻的减少，观察两个电流极性。这种双极激发在自旋转移的单畴模型中是不被期望的。我们认为，在高电流密度下，纵向自旋累积的强烈不对称性会导致双层样本中横向于电流方向的自旋波不稳定性，类似于我们针对单磁性层结报道的情况。
Current-induced magnetic excitations in Co/Cu/Co bilayer nanopillars ($\sim$50 nm in diameter) have been studied experimentally at low temperatures for large applied fields perpendicular to the layers. At sufficiently high current densities excitations, which lead to a decrease in differential resistance, are observed for both current polarities. Such bipolar excitations are not expected in a single domain model of spin-transfer. We propose that at high current densities strong asymmetries in the longitudinal spin accumulation cause spin-wave instabilities transverse to the current direction in bilayer samples, similar to those we have reported for single magnetic layer junctions.