Effect of Ir–Mn composition on exchange bias and thermal stability of spin valves with nano-oxide layers
Effect of Ir–Mn composition on exchange bias and thermal stability of spin valves with nano-oxide layers
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DOI：
10.1063/1.2917396
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发表时间：
2008-05
影响因子：
3.2
通讯作者：
Yong-Hui Liu;J. Cai;W. Lai;G. Yu
中科院分区：
文献类型：
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作者：
Yong-Hui Liu;J. Cai;W. Lai;G. Yu
采用直流磁控溅射技术制备了具有纳米氧化层(NOL)、Ta∕Ni81Fe19∕Ir–Mn∕Co90Fe10∕NOL∕Co90Fe10∕Cu∕Co90Fe10∕NOL∕Ta，的Ir-Mn底钉扎自旋阀。研究了磁阻(MR)、磁化强度和交换偏置随Ir-Mn组分和退火温度的变化。结果表明，含锰量相对较低(58.9-72.4at.%)的Ir-Mn层的自旋阀具有最好的耐热性。对于这些样品，NOL有效地阻碍了Mn的扩散，即使在300°C热处理后，仍有约12.5%的MR值。另一方面，钉扎CoFe层的交换偏置场在Mn含量约为72.4at.%时出现最大值，这与广泛采用的从顶部钉扎NiFe/Ir-Mn体系优化得到的Ir-80at.%Mn不同。此外，含72.4at.%Mn的Ir-Mn/CoFe体系的阻挡温度高于含80.6at.%Mn的Ir-Mn/CoFe体系。结果表明，含锰的Ir-Mn/CoFe钉扎体系具有较高的稳定性。
The Ir–Mn bottom-pinned spin valves with nano-oxide layers (NOLs), Ta∕Ni81Fe19∕Ir–Mn∕Co90Fe10∕NOL∕Co90Fe10∕Cu∕Co90Fe10∕NOL∕Ta, were fabricated by dc magnetron sputtering. The magnetoresistance (MR), magnetization, and exchange bias have been studied as a function of Ir–Mn composition and annealing temperature. It was observed that the spin valves with the Ir–Mn layer containing relatively low Mn content (58.9–72.4at.% Mn) show the best thermal endurance. For these samples, the Mn diffusion is effectively hampered by the NOL with a large MR value of about 12.5% even after annealing at 300°C. On the other hand, the exchange bias field of the pinned CoFe layer shows a maximum at Mn content of about 72.4at.%, which is different from the widely adopted composition, Ir‐80at.% Mn, optimized from the top-pinned NiFe∕Ir–Mn system. Moreover, the blocking temperature of the Ir–Mn∕CoFe system with 72.4at.% Mn is higher than that with 80.6at.% Mn. The present results suggest that the Ir–Mn∕CoFe pinning system with Mn ...