Triplet generation and upper critical field in superconducting spin valves based on CrO2
Triplet generation and upper critical field in superconducting spin valves based on CrO2
复制标题
CrO2 超导自旋阀的三重态产生和上临界场
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
J. Aarts
中科院分区：
文献类型：
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作者：
S. Voltan;Amrita Singh;J. Aarts
最近有报道称，基于半金属CrO2的超导三重态自旋阀(TSV)的临界温度可以达到1K以上，当混合器(F1)和排泄铁磁层(F)之间的磁非共线性达到最大时，就可以实现这一点。在这项工作中，我们从两个方面进一步研究了这种TSV器件：第一，我们给出了fi效应与混合层厚度的关系；第二，我们研究了垂直上临界field Hc2⊥作为温度的函数。厚度依赖关系如预期的那样是非单调的，这进一步证明了这种效应是由于等自旋三重态库珀对的产生，而我们在Hc2⊥-T曲线上观察到的是一个有趣而奇怪的行为：与普遍的线性依赖关系相比，存在明显的偏离，平均斜率受到的抑制比用传统邻近结构的形式可以描述的要大得多。
It has been recently reported that a superconducting triplet spin valve (TSV) based on the half-metallic CrO 2 can show “colossal” variations of the critical temperature, up to more than 1 K. This can be achieved when the magnetic noncollinearity between the mixer (F 1 ) and the drainage ferromagnetic layer (F) is maximized. In this work we investigate further such TSV devices looking at two aspects: first, we present the dependence of the TSV effect on the thickness of the mixer layer; second, we look at the perpendicular upper critical field H c 2 ⊥ as a function of the temperature. The thickness dependence, which is nonmonotonic as expected, represents a further proof that the effect is due to the generation of equal-spin triplet Cooper pairs, while what we observe for the H c 2 ⊥ versus T curves is an interesting and peculiar behavior: there is a clear deviation from the universal linear dependence and the average slope is suppressed much more than what can be described with the formalism used for conventional proximized structures.