Magneto-Optical and Spin-Transfer Switching Properties of Current-Perpendicular-to Plane Spin Valves With Perpendicular Magnetic Anisotropy
Magneto-Optical and Spin-Transfer Switching Properties of Current-Perpendicular-to Plane Spin Valves With Perpendicular Magnetic Anisotropy
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具有垂直磁各向异性的电流垂直于平面自旋阀的磁光和自旋转移切换特性
DOI：
10.1109/tmag.2008.2002615
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发表时间：
2008
影响因子：
2.1
通讯作者：
F. Sato
中科院分区：
文献类型：
--
作者：
K. Aoshima;N. Funabashi;K. Machida;Y. Miyamoto;N. Kawamura;K. Kuga;N. Shimidzu;T. Kimura;Y. Otani;F. Sato
我们评估了具有由 Gd-Fe (4-30 nm) 自由层和 Tb-Fe-Co/CoFe 固定层组成的垂直磁体的自旋阀 (SV) 堆栈的磁光特性，以及具有垂直磁体的电流垂直于平面 (CPP) SV 的自旋转移切换特性。 Gd-Fe自由层在10nm的厚度下具有0.12度的极性克尔旋转θk。 θ<sub>k</sub> 随着 GdFe 厚度的减小而减小，并且当 Gd-Fe 厚度为 6 nm 或更薄时，theta<sub>k</sub> 的符号从正变为负。厚度为 8 nm 时，矫顽力 (H<sub>c</sub>) 最大，饱和磁化强度 (M<sub>s</sub>) 最小。这些现象可以用不均匀的 Gd-Fe 成分来解释。具有 Gd-Fe (10 nm) 自由层的 CPP 自旋阀的磁阻 (MR) 为 0.038%。 CPP SV器件的自由层通过脉冲电流进行切换，其本征切换电流密度为J<sub>c0_P-</sub> <sub>AP</sub>= -3.3×10<sup>7</sup> A/cm<sup>2</sup>和J<sub>c0_</sub> <sub>AP-P</sub>= 4.3×10<sup>7</sup> A/cm<sup>2</sup>，热稳定性为 75，高于所需值 40。垂直磁体对于从自旋转移切换驱动的纳米磁体获取大磁光信号非常有用。
We evaluated the magneto-optical properties of spin-valve (SV) stacks with perpendicular magnets comprised of a Gd-Fe (4-30 nm) free layer and a Tb-Fe-Co/CoFe pinned layer, and the spin-transfer switching properties of current-perpendicular-to-plane (CPP) SVs with the perpendicular magnets. The Gd-Fe free layer had polar Kerr rotation thetas<sub>k</sub> of 0.12deg at a thickness of 10 nm. The thetas<sub>k</sub> reduced with a decrease in GdFe thickness and the sign of thetas<sub>k</sub> switched from positive to negative at a Gd-Fe thickness of 6 nm or thinner. Coercivity (H<sub>c</sub>) was maximum and saturation magnetization (M<sub>s</sub>) was minimum at a thickness of 8 nm. These phenomena may be explained by an inhomogeneous Gd-Fe composition. The CPP spin valves with the Gd-Fe (10 nm) free layer had a magneto-resistance (MR) of 0.038%. The free layer of a CPP SV device was switched by a pulsed current, which exhibited intrinsic switching current densities of J<sub>c0_P-</sub> <sub>AP</sub>= -3.3times10<sup>7</sup> A/cm<sup>2</sup> and J<sub>c0_</sub> <sub>AP-P</sub>= 4.3times10<sup>7</sup> A/cm<sup>2</sup> with a thermal stability of 75, which is above the required value of 40. Perpendicular magnets are very useful for obtaining large magneto-optical signals from nano-magnets driven by spin-transfer switching.