Over the last decade, there has been steady research on superconducting junctions with a ferromagnet as the weak link, and where triplet correlations can transport supercurrents over a substantial distances. Of particular interest are halfmetallic ferromagnets, in which only one spin band is present, so that, presumably, the induced supercurrent is fully spin-polarized. We have earlier reported on a study of triplet transport in planar La0.7Sr0.3MnO3(LSMO) nanostrip Josephson junctions with NbTi superconducting contacts, where we found high values for the supercurrents, and large junction lengths (up to 1.3 μm). Here, we extend that work by studying the dependence of the critical current Ic on the length of the nanostrip between the contacts and the width of the strip. All junctions show strong supercurrents, but we do not observe simple systematics. Apparently, the fabrication process does not allow sufficient control over some of its parameters. To gain more insight in the mechanism for triplet generation at the LSMO/NbTi interface, we also studied the effect of Pt as an interlayer between the LSMO and the NbTi. For this, we etched a NbTi/Pt electrode structure on a full film of LSMO. The results are highly promising, showing sharp superconducting transitions and zero-resistance states being reached at an electrode distance of 2 μm, with indications that larger distances should be feasible.
Triplet Cooper pairs induced in diffusive s-wave superconductors interfaced with strongly spin-polarized magnetic insulators or half-metallic ferromagnets
Coupling of two superconductors through a ferromagnet : evidence for a pi-junction
我们报告的测量约瑟夫森结的临界电流的温度依赖性组成的常规超导银行的Nb和弱铁磁夹层的Cu $_x$ Ni $_{1-x}$合金，与$x$约0.5。随着温度的降低，$I_c$通常会增加，但对于特定厚度的铁磁夹层，发现一个最大值，然后强烈下降到零，之后$I_c$再次上升。这种尖锐的尖点只能通过假设结从高温下的0相状态变为低温下的$π$相状态来解释。
Helical structures in layered magnetic superconductors due to indirect exchange interactions mediated by interlayer tunneling
受最近在RbEuFe中发现的螺旋磁结构的启发，$_{4}$作为$_{4}$，我们研究了由空间分离的超导层和铁磁对准层组成的材料中的磁矩的层间有序性。我们考虑正常和超导间接交换相互作用之间的相互作用介导的导电层之间的隧道。我们制定了一个配方，以评估正常的层间相互作用，通过二维状态密度的孤立层，并表明，对于带小填充物，这种相互作用是典型的铁磁性和短程。最近层相互作用与层间跳跃和面内带宽的平方之比成正比。另一方面，当层间跳跃能超过超导能隙时，超导贡献总是产生反铁磁相互作用，并可能跨越几个层。正常部分和超导部分之间的相互作用引起的挫折可能导致螺旋基态磁位形。四重面内各向异性可以将相邻层中的矩之间的旋转角锁定到$90^\circ$，如在RbEuFe $_{4}$ As $_{4}$中观察到的
Proximity-driven source of highly spin-polarized ac current on the basis of superconductor/weak ferromagnet/superconductor voltage-biased Josephson junction
Transport regimes in tunnel ferromagnetic Josephson junctions
University of Naples Federico II（那不勒斯费德里科二世大学）；Moscow Institute of Physics and Technology（莫斯科物理技术学院）；HSE University（俄罗斯高等经济大学）；QuantWare（QuantWare公司）；Consiglio Nazionale delle Ricerche—ISASI（国家研究委员会-ISASI研究所）；Leibniz Institute for Solid State and Materials Research Dresden (IFW Dresden)（德累斯顿莱布尼茨固体与材料研究所）；Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University（罗蒙诺索夫莫斯科大学斯科别尔琴核物理研究所）
