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arXiv 1801.04732cond-mat.supr-concond-mat.mes-hallcond-mat.str-el
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Nb/Gd/Nb三层膜的磁性和超导Phase Diagram

Magnetic and Superconducting Phase Diagram of Nb/Gd/Nb trilayers

Yu. N. Khaydukov, A. S. Vasenko, E. A. Kravtsov, V. V. Progliado, V. D. Zhaketov, A. Csik, Yu. V. Nikitenko, A. V. Petrenko, T. Keller, A. A. Golubov, M. Yu. Ku… 展开作者

Yu. N. Khaydukov, A. S. Vasenko, E. A. Kravtsov, V. V. Progliado, V. D. Zhaketov, A. Csik, Yu. V. Nikitenko, A. V. Petrenko, T. Keller, A. A. Golubov, M. Yu. Kupriyanov, V. V. Ustinov, V. L. Aksenov, B. Keimer

摘要:

本文研究了Nb(25 nm)/Gd($d_f$)/Nb(25 nm)超导/铁磁体(S/F)混合结构的结构、磁性和超导性质。样品的结构表征,包括仔细确定的层厚度,进行使用中子和X-射线散射与深度敏感质谱仪的帮助下。样品的磁化强度由SQUID磁强计和极化中子反射仪测定,并显示所有样品的磁有序的存在下,最薄的Gd(0.8nm)层。的中子自旋不对称性的分析,使我们能够证明的情况下,磁死层的交界处的Gd层间厚度大于一个单层。测量的超导转变温度$T_c(d_f)$的相关性具有阻尼振荡行为,其具有在$d_f$ = 3 nm处的最小值和在$d_f$ = 4 nm处的随后的最大值的良好定义的位置; Jiang等人,PRB 54,6119)。根据Usadel方程对$T_c(d_f)$依赖性的分析表明,在$d_f$ = 3 nm处观察到的最小值可以用Gd中超导关联长度为$ξ_f \approx 4$ nm的高透明S/F界面的“$0$“到“$π$“相变来描述。该穿透长度比强铁磁体(如Fe、Co或Ni)高几倍,从而简化了具有$d_f \sim ξ_f$的S/F结构的制备,这在超导自旋电子学中是热门话题。

英文摘要:

We report on a study of the structural, magnetic and superconducting properties of Nb(25nm)/Gd($d_f$)/Nb(25nm) hybrid structures of a superconductor/ ferromagnet (S/F) type. The structural characterization of the samples, including careful determination of the layer thickness, was performed using neutron and X-ray scattering with the aid of depth sensitive mass-spectrometry. The magnetization of the samples was determined by SQUID magnetometry and polarized neutron reflectometry and the presence of magnetic ordering for all samples down to the thinnest Gd(0.8nm) layer was shown. The analysis of the neutron spin asymmetry allowed us to prove the absence of magnetically dead layers in junctions with Gd interlayer thickness larger than one monolayer. The measured dependence of the superconducting transition temperature $T_c(d_f)$ has a damped oscillatory behavior with well defined positions of the minimum at $d_f$=3nm and the following maximum at $d_f$=4nm; the behavior, which is in qualitative agreement with the prior work (J.S. Jiang et al, PRB 54, 6119). The analysis of the $T_c(d_f)$ dependence based on Usadel equations showed that the observed minimum at $d_f$=3nm can be described by the so called "$0$" to "$π$" phase transition of highly transparent S/F interfaces with the superconducting correlation length $ξ_f \approx 4$nm in Gd. This penetration length is several times higher than for strong ferromagnets like Fe, Co or Ni, simplifying thus preparation of S/F structures with $d_f \sim ξ_f$ which are of topical interest in superconducting spintronics.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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