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arXiv 2209.15366cond-mat.supr-concond-mat.mes-hall
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Ni-Nb铁磁-超导双层结构中不存在磁相互作用

Absence of magnetic interactions in Ni-Nb ferromagnet-superconductor bilayers

Nathan Satchell, P. Quarterman, J. A. Borchers, Gavin Burnell, Norman O. Birge

AI总结:

本文通过极化中子反射和约瑟夫森结两种独立技术,在零外加场下检验Ni-Nb铁磁-超导双层中的电磁邻近效应,未观测到任何磁信号,并给出其大小上限为±0.27 mT,提示现有理论可能需要扩展。

摘要:

对铁磁-超导混合体系的研究揭示了相互竞争的电子有序之间的磁相互作用。电磁(EM)邻近效应预言,在邻近铁磁体的超导体内部会形成自发矢势。在本工作中,我们使用Nb超导层和Ni铁磁层来检验这种磁相互作用。我们采用极化中子反射测量和探测约瑟夫森结这两种互补但相互独立的技术,在接近零外加场的条件下探测超导层内部的磁响应。在该条件下,迈斯纳屏蔽可以忽略不计,因此我们的测量只考察来自邻近效应的额外磁贡献和屏蔽贡献。我们报告在零外加场下未观察到任何源自EM邻近效应的信号。我们的观测结果表明,要么EM邻近效应低于我们两项实验的检测分辨率,要么可能揭示一种需要扩展当前理论的新现象。根据我们的测量,我们估计在Ni-Nb样品中零场EM邻近效应的大小上限为±0.27 mT。

英文摘要:

Studies of ferromagnet-superconductor hybrid systems have uncovered magnetic interactions between the competing electronic orderings. The electromagnetic (EM) proximity effect predicts the formation of a spontaneous vector potential inside a superconductor placed in proximity to a ferromagnet. In this work, we use a Nb superconducting layer and Ni ferromagnetic layer to test for such magnetic interactions. We use the complementary, but independent, techniques of polarised neutron reflectometry and detection Josephson junctions to probe the magnetic response inside the superconducting layer at close to zero applied field. In this condition, Meissner screening is negligible, so our measurements examine only additional magnetic and screening contributions from proximity effects. We report the absence of any signals originating from EM proximity effect in zero applied field. Our observations indicate that either EM proximity effect is below the detection resolution of both of our experiments or may indicate a new phenomenon that requires extension of current theory. From our measurements, we estimate a limit of the size of the zero field EM proximity effect in our Ni-Nb samples to be $\pm0.27$ mT.

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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