Magnetic field resistant quantum interferences in bismuth nanowires based Josephson junctions

We investigate proximity induced superconductivity in micrometer-long bismuth nanowires con- nected to superconducting electrodes with a high critical field. At low temperature we measure a supercurrent that persists in magnetic fields as high as the critical field of the electrodes (above 11 T). The critical current is also strongly modulated by the magnetic field. In certain samples we find regular, rapid SQUID-like periodic oscillations occurring up to high fields. Other samples ex- hibit less periodic but full modulations of the critical current on Tesla field scales, with field-caused extinctions of the supercurrent. These findings indicate the existence of low dimensionally, phase coherent, interfering conducting regions through the samples, with a subtle interplay between orbital and spin contributions. We relate these surprising results to the electronic properties of the surface states of bismuth, strong Rashba spin-orbit coupling, large effective g factors, and their effect on the induced superconducting correlations.Comment: 5 page

Josephson coupling across a long single-crystalline Cu nanowire

© 2017 Author(s).We report on a fabrication method and electron-transport measurements for submicron Josephson junctions formed by Cu nanowires coupling to superconducting planar Nb electrodes. The Cu nanowires with a resistivity of ρ C:1 μ Ω cm at low temperatures consisting of single-crystalline segments have been obtained by templated electrodeposition using anodic aluminum oxide as a porous matrix. The current-voltage characteristics of the devices have been studied as a function of temperature and magnetic field. For all junctions, the critical current monotonically decreases with a magnetic field. The measured temperature and magnetic field dependencies are consistent with the model for one-dimensional diffusive superconductor/normal metal/superconductor (SNS) Josephson junctions within the quasiclassical theory of superconductivity

Magnetoresistance of a single polycrystalline nickel nanowire

© 2019 Author(s). We report the magnetoresistance study of an individual polycrystalline nickel nanowire at temperature T = 10 K. Transport measurements have indicated a large coercive field of the nanowire, justified by the polycrystalline structure of the studied sample, where both magnetocrystalline anisotropy of randomly oriented grains and effective uniaxial anisotropy at the grain boundaries enhance the coercive field. Magnetization reversal studied with micromagnetic simulations occurs via the curling mode when vortices are nucleated and propagate along the nanowire, and propagation is inhibited at grain boundaries. The applicability of micromagnetic simulations is confirmed by a good agreement between experimental and simulated magnetoresistance curves

Magnetoresistance of a single polycrystalline nickel nanowire

© 2019 Author(s). We report the magnetoresistance study of an individual polycrystalline nickel nanowire at temperature T = 10 K. Transport measurements have indicated a large coercive field of the nanowire, justified by the polycrystalline structure of the studied sample, where both magnetocrystalline anisotropy of randomly oriented grains and effective uniaxial anisotropy at the grain boundaries enhance the coercive field. Magnetization reversal studied with micromagnetic simulations occurs via the curling mode when vortices are nucleated and propagate along the nanowire, and propagation is inhibited at grain boundaries. The applicability of micromagnetic simulations is confirmed by a good agreement between experimental and simulated magnetoresistance curves

Josephson coupling across a long single-crystalline Cu nanowire

© 2017 Author(s).We report on a fabrication method and electron-transport measurements for submicron Josephson junctions formed by Cu nanowires coupling to superconducting planar Nb electrodes. The Cu nanowires with a resistivity of ρ C:1 μ Ω cm at low temperatures consisting of single-crystalline segments have been obtained by templated electrodeposition using anodic aluminum oxide as a porous matrix. The current-voltage characteristics of the devices have been studied as a function of temperature and magnetic field. For all junctions, the critical current monotonically decreases with a magnetic field. The measured temperature and magnetic field dependencies are consistent with the model for one-dimensional diffusive superconductor/normal metal/superconductor (SNS) Josephson junctions within the quasiclassical theory of superconductivity