Experimental Study of the Variation in Oscillation Characteristics of Point-Contact-Based Spin-Torque Oscillators
Experimental Study of the Variation in Oscillation Characteristics of Point-Contact-Based Spin-Torque Oscillators
复制标题
基于点接触的自旋扭矩振荡器振荡特性变化的实验研究
DOI：
10.1109/lmag.2012.2208098
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发表时间：
2012
影响因子：
1.2
通讯作者：
D. Ricketts
中科院分区：
文献类型：
--
作者：
S. Tamaru;D. Ricketts
本文对圆形点接触式自旋力矩振荡器（PC-STO）的振荡特性变化进行了实验研究。我们首先测量了多个相同制造的PC-STO的振荡行为，然后在PC-STO上进行了相同的测量，并旋转了偏置场的方位角。<formula formulatype="inline"><tex Notation="TeX"></tex></formula>我们的研究结果表明，相当大的设备到设备的变化之间相同的PC-STO。更引人注目的是在一个小<formula formulatype="inline"><tex Notation="TeX">的$\varphi$</tex></formula>旋转，这是完全不符合几何对称的设备在一个单一的PC-STO的大的变化。这些结果表明，巨磁电阻堆具有某种形式的微结构的不均匀性，这会导致强烈的<formula formulatype="inline"><tex Notation="TeX">$\varphi$</tex></formula>依赖的振荡行为，最终导致在设备到设备的变化。根据这些观测结果，讨论了不均匀性的可能来源。
This paper presents an experimental study of the variation in oscillation characteristics of circular point-contact-based spin-torque oscillators (PC-STOs). We first measured the oscillation behavior of multiple, identically fabricated PC-STOs, then made the same measurements on a PC-STO and rotated the azimuth angle of the bias field <formula formulatype="inline"><tex Notation="TeX">$\varphi$</tex></formula>. Our results show considerable device-to-device variations among identical PC-STOs. More striking is large changes within a single PC-STO for a small <formula formulatype="inline"><tex Notation="TeX">$\varphi$</tex></formula> rotation, which is totally inconsistent with the geometrical symmetry of the device. These results suggest that the giant magnetoresistance stack has some form of microstructural inhomogeneity, which causes a strong <formula formulatype="inline"><tex Notation="TeX">$\varphi$</tex></formula> dependence of the oscillation behavior, eventually resulting in the device-to-device variation. Some possible sources of the inhomogeneity are discussed based on these observation results.