Absence of magnetic interactions in Ni-Nb ferromagnet-superconductor bilayers
Absence of magnetic interactions in Ni-Nb ferromagnet-superconductor bilayers
复制标题
Ni-Nb 铁磁体-超导体双层中不存在磁相互作用
DOI：
10.1088/1361-6668/acc430
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发表时间：
2023
影响因子：
3.6
通讯作者：
Satchell N
中科院分区：
文献类型：
--
作者：
Satchell N
铁磁-超导混合系统的研究揭示了竞争电子有序之间的磁相互作用。电磁（EM）邻近效应预测了在铁磁体附近放置的超导体内部自发矢量势的形成。在这项工作中，我们使用Nb超导层和Ni铁磁层来测试这种磁相互作用。我们使用互补的，但独立的，极化中子反射计和检测约瑟夫森结探测超导层内的磁响应在接近零的外加磁场的技术。在这种情况下，迈斯纳屏蔽是可以忽略不计的，所以我们的测量只检查额外的磁性和屏蔽贡献的邻近效应。我们报告的情况下，没有任何信号来自EM邻近效应在零施加领域。我们的观察表明，无论是EM邻近效应低于我们的实验的检测分辨率，或可能表明一个新的现象，需要扩展目前的理论。根据我们的测量，我们估计Ni-Nb样品中零场EM邻近效应的大小极限为±0.27 mT。
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 polarized 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±0.27 mT.