Guy Deutscher - Academia.edu (original) (raw)
Papers by Guy Deutscher
Physica C: Superconductivity, 2010
We studied superconducting to normal state current-driven transitions in Ferromagnetic Cobalt/Cob... more We studied superconducting to normal state current-driven transitions in Ferromagnetic Cobalt/Cobalt Oxide/Superconducting Indium stripes of widths ranging from 3 lm to 20 lm. The narrower stripes can be set up in a high or low critical current state by driving the magnetic domain structure of the thin Co film either in an almost uniform or non-uniform state of magnetization. In the first case in slightly sub critical currents there is a spontaneous superconducting to normal state transition. In the latter the transition is preceded by the development of normal domains. The spontaneous transition as well as the normal domains are triggered by flux jumps.
The properties of granular superconductors are reviewed, with emphasis on the specific properties... more The properties of granular superconductors are reviewed, with emphasis on the specific properties that result from their inhomogeneous structure at the grain-size scale. Percolation theories are shown to provide a useful basis for the understanding of critical current and heat capacity data.
Physical Review B, 2005
We studied the tunneling density of states in YBCO films under strong currents flowing along node... more We studied the tunneling density of states in YBCO films under strong currents flowing along node directions. The currents were induced by fields of up to 32.4T parallel to the film surface and perpendicular to the CuO2 planes. We observed a remarkable change in the tunneling conductance at high fields where the gap-like feature shifts discontinuously from 15meV to a lower bias of 11meV, becoming more pronounced as the field increases. The effect takes place in increasing fields around 9T and the transition back to the initial state occurs around 5T in decreasing fields.
Physica C: Superconductivity, 1992
ABSTRACT
Physica C: Superconductivity, 1999
c-axis-oriented YBCO films with T s 90 K and low macroscopic defect density were grown reproducib... more c-axis-oriented YBCO films with T s 90 K and low macroscopic defect density were grown reproducibly on STO, LAO c Ž .
Physica C: Superconductivity, 2007
ABSTRACT We present a study of the influence of zinc impurities on the zero bias conductance peak... more ABSTRACT We present a study of the influence of zinc impurities on the zero bias conductance peak (ZBCP) in tunnel junctions grown on [I 10] oriented optimally doped YBa2Cu3O7-x thin films. We report three specific results: (i) the ratio of the energy gap to the critical temperature remains constant; (ii) there is a weakening of the ZBCP; and (iii) the ZBCP field splitting is different from that in undoped YBCO, with a very small hysteresis and an overall field dependence incompatible with node removal. (c) 2007 Elsevier B.V. All rights reserved.
Applied Physics Letters, 2008
We fabricated nanoscale ferromagnetic (F) Nickel/superconducting (S) indium junctions which show ... more We fabricated nanoscale ferromagnetic (F) Nickel/superconducting (S) indium junctions which show that spin polarization effects on the contact conductance can be observed in a planar geometry. The data demonstrate that the Andreev-Saint-James [Sov. Phys. JETP 19, 1228 (1964) and J. Phys. (Paris) 25, 899 (1964)] electron-hole reflections at the F/S interface, which are sensitive to the polarization of the F
Applied Physics Letters, 2009
We have studied superconducting to normal state current-driven transitions in ferromagnetic Co/Co... more We have studied superconducting to normal state current-driven transitions in ferromagnetic Co/Co oxide/superconducting In stripes of widths ranging from 3 to 20 m. The narrower stripes can be set up in a high or low critical current state by driving the magnetic domain structure of the thin Co film either in an almost uniform or nonuniform state of magnetization. In the latter the critical current transition is preceded by the development of normal domains, whose dynamics are determined by the Co magnetization pattern.
Applied Physics Letters, 1975
Granular aluminum thin films have been used to produce rf-pumped SQUID's. Owing to the low c... more Granular aluminum thin films have been used to produce rf-pumped SQUID's. Owing to the low critical current density of the granular superconductors, SQUID's with weak links as wide as 40 mum are observed to operate even far below Tc.
Physica C: Superconductivity, 2010
We studied superconducting to normal state current-driven transitions in Ferromagnetic Cobalt/Cob... more We studied superconducting to normal state current-driven transitions in Ferromagnetic Cobalt/Cobalt Oxide/Superconducting Indium stripes of widths ranging from 3 lm to 20 lm. The narrower stripes can be set up in a high or low critical current state by driving the magnetic domain structure of the thin Co film either in an almost uniform or non-uniform state of magnetization. In the first case in slightly sub critical currents there is a spontaneous superconducting to normal state transition. In the latter the transition is preceded by the development of normal domains. The spontaneous transition as well as the normal domains are triggered by flux jumps.
The properties of granular superconductors are reviewed, with emphasis on the specific properties... more The properties of granular superconductors are reviewed, with emphasis on the specific properties that result from their inhomogeneous structure at the grain-size scale. Percolation theories are shown to provide a useful basis for the understanding of critical current and heat capacity data.
Physical Review B, 2005
We studied the tunneling density of states in YBCO films under strong currents flowing along node... more We studied the tunneling density of states in YBCO films under strong currents flowing along node directions. The currents were induced by fields of up to 32.4T parallel to the film surface and perpendicular to the CuO2 planes. We observed a remarkable change in the tunneling conductance at high fields where the gap-like feature shifts discontinuously from 15meV to a lower bias of 11meV, becoming more pronounced as the field increases. The effect takes place in increasing fields around 9T and the transition back to the initial state occurs around 5T in decreasing fields.
Physica C: Superconductivity, 1992
ABSTRACT
Physica C: Superconductivity, 1999
c-axis-oriented YBCO films with T s 90 K and low macroscopic defect density were grown reproducib... more c-axis-oriented YBCO films with T s 90 K and low macroscopic defect density were grown reproducibly on STO, LAO c Ž .
Physica C: Superconductivity, 2007
ABSTRACT We present a study of the influence of zinc impurities on the zero bias conductance peak... more ABSTRACT We present a study of the influence of zinc impurities on the zero bias conductance peak (ZBCP) in tunnel junctions grown on [I 10] oriented optimally doped YBa2Cu3O7-x thin films. We report three specific results: (i) the ratio of the energy gap to the critical temperature remains constant; (ii) there is a weakening of the ZBCP; and (iii) the ZBCP field splitting is different from that in undoped YBCO, with a very small hysteresis and an overall field dependence incompatible with node removal. (c) 2007 Elsevier B.V. All rights reserved.
Applied Physics Letters, 2008
We fabricated nanoscale ferromagnetic (F) Nickel/superconducting (S) indium junctions which show ... more We fabricated nanoscale ferromagnetic (F) Nickel/superconducting (S) indium junctions which show that spin polarization effects on the contact conductance can be observed in a planar geometry. The data demonstrate that the Andreev-Saint-James [Sov. Phys. JETP 19, 1228 (1964) and J. Phys. (Paris) 25, 899 (1964)] electron-hole reflections at the F/S interface, which are sensitive to the polarization of the F
Applied Physics Letters, 2009
We have studied superconducting to normal state current-driven transitions in ferromagnetic Co/Co... more We have studied superconducting to normal state current-driven transitions in ferromagnetic Co/Co oxide/superconducting In stripes of widths ranging from 3 to 20 m. The narrower stripes can be set up in a high or low critical current state by driving the magnetic domain structure of the thin Co film either in an almost uniform or nonuniform state of magnetization. In the latter the critical current transition is preceded by the development of normal domains, whose dynamics are determined by the Co magnetization pattern.
Applied Physics Letters, 1975
Granular aluminum thin films have been used to produce rf-pumped SQUID's. Owing to the low c... more Granular aluminum thin films have been used to produce rf-pumped SQUID's. Owing to the low critical current density of the granular superconductors, SQUID's with weak links as wide as 40 mum are observed to operate even far below Tc.