Anomalous magneto-resistance of Ni-nanowire/Nb hybrid system

Abstract

We examine the influence of superconductivity on the magneto-transport properties of a ferromagnetic Ni nanowire connected to Nb electrodes. We show experimentally and confirm theoretically that the Nb/Ni interface plays an essential role in the electron transport through the device. Just below the superconducting transition, a strong inverse proximity effect from the nanowire suppresses superconducting correlations at Nb/Ni interfaces, resulting in a conventional anisotropic magneto-resistive response. At lower temperatures however, the Nb electrodes operate as superconducting shunts. As the result, the magneto-resistance exhibits a strongly growing hysteretic behavior accompanied by a series of saw-like jumps. The latter are associated with the penetration/escape of individual Abrikosov vortices that influence non-equilibrium processes at the Nb/Ni interface. These effects should be taken into account when designing superconducting quantum nano-hybrids involving ferromagnetic nanowires.

Anisotropic Magnetoresistance Effect of Nickel Nanowires

“…The average of all magnetic anisotropies approximates to zero because the Ni NW is composed of the nanocrystallites with random orientations. The magnetic hysteresis loop confirms our samples to be the single-domain magnets [12,14,15] and the valid value of H d .…”

“…The AMR effect occurs not only in bulk materials [10][11][12] but also in nanomaterials such as the ferromagnetic nanowires (NWs) [11][12][13]. The magnetoresistance of NWs is easily in control of the shape and the size of wires for making the magnetic devices such as memory, sensor, signal processing, logic [10][11][12]14].…”

Environment-induced overheating phenomena in Au-nanowire based Josephson junctions

“…The resistance of the measured sample consists of two parts . Here is the resistance of the middle segment of NW, whereas is the resistance of the region overlapped by electrode 11 . The temperature dependence of the latter term is associated with specific boundary resistance , which is proportional 12 – 17 to .…”

“…In our model we assume that temperature dependence mostly correspond with Andreev reflection processes in the considered range of temperatures and . The approximation of the intermediate part of R ( T ) dependence enables one to estimate material parameters of the device 11 . The best fit is shown in Fig.…”

“…I ( V ) measured in 2P scheme are identical to 4PI case and are not shown in figure. The hysteresis is associated with the overheating of the electronic system on retrapping 11 . Though, I ( V ) curves measured on the same junction in 4PS scheme (yellow line in Fig.…”