Nonlocal injection of spin current into a superconducting Nb wire

Abstract

Pure spin current injection into a superconductive Nb was demonstrated experimentally by employing a nonlocal spin absorption technique in a multiterminal lateral structure. From the reduction in spin signals, we found the absorption efficiency remained almost unchanged even after superconducting transition. The Nb/Cu interface properties were also complementarily examined by using a Nb/Cu/Nb junction incorporated in the same device, revealing superconductivity below the transition temperature. These experimental results support that the pure spin current can be absorbed into a superconductive Nb wire with almost the same efficiency as in a normal state.

Significant change of spin transport property in Cu/Nb bilayer due to superconducting transition

“…This strong reduction of spin signal clearly indicates that the NC Nb layer strongly absorbs the spin current flowing in the Cu layer because of the strong spin relaxation of the Nb, as schematically shown in the left-hand side of Fig. 4 6 16 34 . The nonlocal spin valve curve measured at 2.3 K is shown in Fig.…”

“…The combination between the spin and super-conducting (SC) transports is also expected to provide intriguing transport properties, leading to an emerging field in spintronics because a superconductor itself has great potential for future nanoelectronic applications such as Josephson circuit and quantum computing 9 10 . Although a number of experimental studies have been performed 11 12 13 14 15 16 17 18 19 20 21 , several intriguing phenomena suggested in theoretical study have not been demonstrated 22 23 24 . Moreover, the experimental study on subgap transports such as a crossed Andreev reflection and a spin triplet proximity effect have still exciting topics in superconducting spintronics because of their fantastic properties 25 26 27 28 29 .…”

“…To investigate aforementioned phenomena in more detail, use of the pure spin currents yields several advantages compared with the spin-polarized current because the charge current induces spin-independent extrinsic effects such as the Joule heating and Oersted field 15 16 . The pure spin current is, in general, generated by nonlocal electrical spin injection using the laterally configured ferromagnetic/nonmagnetic hybrid structures 30 .…”

Nonlocal ordinary magnetoresistance in indium arsenide

“…Here the word "nonlocal" means probes of voltmeter were both placed on one side of probes of current source. This geometry has also been broadly applied in nonlocal spin injection research [18][19][20][21][22]. In contrast, local geometry means that the probes of voltmeter were both placed between the probes of current source as shown in Fig.…”

First-principles calculation of the Andreev conductance of carbon wires

“…Normal-metal-superconductor (N-S) hybrid structures have attracted continuous attention in the past few decades motivated by their broad application prospect in superconducting nanoelectronics, spintronics, as well as quantum logic circuits based on superconductors. [1][2][3][4][5][6] The quantum physics associated with the coherence transport properties in N-S hybrid structures has been extensively investigated theoretically and experimentally. 7,8 At the N-S interface, Andreev reflection occurs, where an electron in the normal metal is reflected as a hole and a Cooper pair appears in the superconductor.…”