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Title: Josephson Effect in the Micron and Submicron YBCO Constrictions Fabricated Using the Femtosecond Laser Technique

Abstract

A femtosecond laser was used successfully to fabricate planar micron and submicron-sized constrictiontype Josephson junctions on YBa{sub 2}Cu{sub 3}O{sub 7−x} thin films. A simple program using G-code (control systems) programming language was written to control the movement of the sample stage during the etching process. The constriction’s geometry was investigated using both atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrical transport measurements were performed at different temperatures. Shapiro steps were observed and analyzed. The micron-sized constriction shows a linear relationship for the measured critical current against the temperature which is consistent with the behavior of an S–s’–Stype Josephson junction where “S” stands for a bulk superconductive material that is untouched by the laser and “s”’ is superconducting material whose critical temperature is lower than the value of “S” In the case of the narrower submicronsized constriction, the measured critical current dependence with temperature shows an exponential decay, which is consistent with the behavior of the long S–N–Stype Josephson junction where “N” stands for a normal material. A model is proposed to describe the observed behavior by considering the effect of sample heating during the constriction’s fabrication.

Authors:
 [1]; ;  [2];  [3]
  1. University of South Africa, Department of Electrical and Mining Engineering (South Africa)
  2. CSIRO Manufacturing (Australia)
  3. University of South Africa, Physics Department (South Africa)
Publication Date:
OSTI Identifier:
22771300
Resource Type:
Journal Article
Journal Name:
Journal of Superconductivity and Novel Magnetism
Additional Journal Information:
Journal Volume: 31; Journal Issue: 5; Other Information: Copyright (c) 2018 Springer Science+Business Media, LLC, part of Springer Nature; Article Copyright (c) 2017 Springer Science+Business Media, LLC; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1557-1939
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMIC FORCE MICROSCOPY; BARIUM OXIDES; COPPER OXIDES; CRITICAL CURRENT; CRITICAL TEMPERATURE; ELECTRIC CONDUCTIVITY; ETCHING; FABRICATION; G CODES; HIGH-TC SUPERCONDUCTORS; JOSEPHSON EFFECT; JOSEPHSON JUNCTIONS; LASERS; SCANNING ELECTRON MICROSCOPY; THIN FILMS; YTTRIUM OXIDES

Citation Formats

Umenne, Patrice, Lam, Simon, Du, Jia, and Srinivasu, V. V., E-mail: vallavs@unisa.ac.za. Josephson Effect in the Micron and Submicron YBCO Constrictions Fabricated Using the Femtosecond Laser Technique. United States: N. p., 2018. Web. doi:10.1007/S10948-017-4371-3.
Umenne, Patrice, Lam, Simon, Du, Jia, & Srinivasu, V. V., E-mail: vallavs@unisa.ac.za. Josephson Effect in the Micron and Submicron YBCO Constrictions Fabricated Using the Femtosecond Laser Technique. United States. doi:10.1007/S10948-017-4371-3.
Umenne, Patrice, Lam, Simon, Du, Jia, and Srinivasu, V. V., E-mail: vallavs@unisa.ac.za. Tue . "Josephson Effect in the Micron and Submicron YBCO Constrictions Fabricated Using the Femtosecond Laser Technique". United States. doi:10.1007/S10948-017-4371-3.
@article{osti_22771300,
title = {Josephson Effect in the Micron and Submicron YBCO Constrictions Fabricated Using the Femtosecond Laser Technique},
author = {Umenne, Patrice and Lam, Simon and Du, Jia and Srinivasu, V. V., E-mail: vallavs@unisa.ac.za},
abstractNote = {A femtosecond laser was used successfully to fabricate planar micron and submicron-sized constrictiontype Josephson junctions on YBa{sub 2}Cu{sub 3}O{sub 7−x} thin films. A simple program using G-code (control systems) programming language was written to control the movement of the sample stage during the etching process. The constriction’s geometry was investigated using both atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrical transport measurements were performed at different temperatures. Shapiro steps were observed and analyzed. The micron-sized constriction shows a linear relationship for the measured critical current against the temperature which is consistent with the behavior of an S–s’–Stype Josephson junction where “S” stands for a bulk superconductive material that is untouched by the laser and “s”’ is superconducting material whose critical temperature is lower than the value of “S” In the case of the narrower submicronsized constriction, the measured critical current dependence with temperature shows an exponential decay, which is consistent with the behavior of the long S–N–Stype Josephson junction where “N” stands for a normal material. A model is proposed to describe the observed behavior by considering the effect of sample heating during the constriction’s fabrication.},
doi = {10.1007/S10948-017-4371-3},
journal = {Journal of Superconductivity and Novel Magnetism},
issn = {1557-1939},
number = 5,
volume = 31,
place = {United States},
year = {2018},
month = {5}
}