Fabrication and characterization of PbIn-Au-PbIn superconducting junctions

Abstract

We report on the fabrication and measurement results of the electrical transport properties of superconductor-normal metalsuperconductor (SNS) weak links, made of PbIn superconductor and Au metal. The maximum supercurrent reaches up to ~ 6 A at T = 2.3 K and the supercurrent persists even at T = 4.7 K. Magnetic field dependence of the critical current is consistent with a theoretical fit using the narrow junction model. The superconducting quantum interference device (SQUID) was also fabricated using two PbIn-Au-PbIn junctions connected in parallel. Under perpendicular magnetic field, we clearly observed periodic oscillations of dV/dI with a period of magnetic flux quantum threading into the supercurrent loop of the SQUID. Our fabrication methods would provide an easy and simple way to explore the superconducting proximity effects without ultra-low-temperature cryostats.

Gate-controlled Supercurrent in Ballistic InSb Nanoflag Josephson Junctions

“…13 Thus, the intensity of the first side-lobes might be anomalously small which precludes their observation in our experiment. On the other hand, such anomalous magnetic interference patterns, with a monotonous decay, were reported previously in similar geometries 36,37,46,47 and were attributed to geometric factors. 36,46,[48][49][50][51][52][53] Besides, the magnetic flux through the junction is Φ = B • A, with A the junction area, A = W (L + 2λ L ).…”

Higher harmonic resistance oscillations in micro-bridge superconducting Nb ring

“…8) However, the detailed mechanism of such intriguing resistance oscillations has not been elucidated yet. Even for devices with d ,  x similar higher harmonic patterns can be seen, 9,10) depending on the shunt resistance, capacitance, and loop inductance in the superconducting ring-shaped devices. 3) From the viewpoint of application, such higher harmonic components have to be suppressed in order to realize the normal operation of SQUID, 11) but on the contrary, a high-performance magnetic sensor can be expected by controlling the higher harmonic components.…”

Superconducting quantum interference devices made of Sb-doped Bi2Se3 topological insulator nanoribbons

“…2a and Table . 1, respectively. Two JJs, fabricated on top of the Sb-doped Bi 2 Se 3 TI NR with PbIn superconducting electrodes, were connected to each other to form a superconducting loop [25,26]. Geometrical dimensions of our devices are listed in Table 1.…”

“…1b. The PbIn electrodes showed a superconducting transition at temperature T c = 6.8 K, while the critical magnetic field was estimated to be H c,perp = 0.74 T (H c,para = 1.2 T) under a perpendicular (parallel) magnetic field [26]. The electrical transport properties of the TI NR-based SQUIDs were measured using a closed-cycle 4 He cryostat (Seongwoo Instruments Inc.) and 3 He refrigerator (Cryogenic Ltd.) which have a base temperature of 2.4 and 0.3 K, respectively.…”