High giant magnetoresistance and thermal annealing effects in perpendicular magnetic [Co/Ni]N-based spin valves
High giant magnetoresistance and thermal annealing effects in perpendicular magnetic [Co/Ni]N-based spin valves
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DOI：
10.1063/1.3158068
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发表时间：
2009-07-01
影响因子：
3.2
通讯作者：
Jin, Q. Y.
中科院分区：
文献类型：
--
作者：
Li, Zhenya;Zhang, Zongzhi;Jin, Q. Y.
研究了以垂直磁性[Co/Ni](N)多层膜为自由层和参考层的赝型和FeMn型自旋阀的热稳定性和巨磁电阻(GMR)。观察到的赝自旋阀的巨磁电阻比高达7.7%，但在200℃的垂直场中退火后，巨磁电阻迅速下降到1.0%以下。温度稳定性差归因于自由多层膜和参考多层膜的同时开关，这是由于失去了它们的矫顽力差。相反，具有类似结构的FeMn偏置样品的GMR信号略低，为6.5%，但表现出更好的热稳定性，GMR还原发生在高于300℃的高温下。这种GMR还原是由于Mn的扩散和垂直各向异性的降低。
The thermal stability and giant magnetoresistance (GMR) of pseudo- and FeMn-biased spin valves with perpendicular magnetic [Co/Ni](N) multilayer as free and reference layers are investigated. The observed GMR ratio for the pseudo-spin-valve is as high as 7.7%, but it rapidly decreases below 1.0% after annealing in a perpendicular field at 200 degrees C. Such poor temperature stability is ascribed to simultaneous switching of the free and reference multilayers caused by loss of their coercivity difference. In contrast, an FeMn-biased sample with a similar structure has a slightly lower GMR signal of 6.5% but exhibits much better thermal stability, with the GMR reduction occurring at an elevated anneal temperature of over 300 degrees C. This GMR reduction is due to Mn diffusion and a reduction in perpendicular anisotropy.