论文标题
节点超导交换耦合
Nodal superconducting exchange coupling
论文作者
论文摘要
相当于巨型磁化率的超导导向涉及在两个铁磁层之间放置薄膜超导体。由于磁交换能的相互作用和超导凝结物，因此从平行（P）到反平行（P）到反平行（P）到反平行（P）的磁化对齐的变化会导致超导转变温度（ΔTC）的正变化。 ΔTC的幅度与超导体厚度（DS）呈呈缩放，当DS超过DE Gennes预测的超导相干长度（ξ）时为零。在这里，我们报告了一种超导旋转阀效应，该效应涉及一种不同的潜在机制，该机制超出了DE Gennes，在该机制中，在D-Wave超级导体超级YBA2CU3O7-Δ（Ybco）之间，在D-Wave超导体超级导体超级Yba2cu3o7-Δ（Ybco）上的nodal quasiparticle-excitation态确定了indersant in Insteraig Layers， PR0.8CA0.2MNO3。我们观察到ΔTC值，即以ΔTC在长度尺度上振荡2 K的ΔTC值超过100ξ，并且对于DS的特定值，我们发现超导状态增强了反平行的磁化对齐。这些结果为全氧化物超导记忆铺平了道路，其中超导能调节磁态。
The superconducting equivalent of giant magnetoresistance, involves placing a thin-film superconductor between two ferromagnetic layers. A change of magnetization-alignment in such a superconducting spin-valve from parallel (P) to antiparallel (AP) creates a positive shift in the superconducting transition temperature (ΔTc) due to an interplay of the magnetic exchange energy and the superconducting condensate. The magnitude of ΔTc scales inversely with the superconductor thickness (dS) and is zero when dS exceeds the superconducting coherence length (ξ) as predicted by de Gennes. Here, we report a superconducting spin-valve effect involving a different underlying mechanism that goes beyond de Gennes in which magnetization-alignment and ΔTc are determined by the nodal quasiparticle-excitation states on the Fermi surface of the d-wave superconductor YBa2Cu3O7-δ (YBCO) grown between insulating layers of ferromagnetic Pr0.8Ca0.2MnO3. We observe ΔTc values that approach 2 K with ΔTc oscillating with dS over a length scale exceeding 100 ξ and, for particular values of dS, we find that the superconducting state reinforces an antiparallel magnetization-alignment. These results pave the way for all-oxide superconducting memory in which superconductivity modulates the magnetic state.
