"JOURNAL OF RADIO ELECTRONICS"  N 3, 2013

contents             full texthtml,   pdf   

Optimization of electrical and structural parameters of YBa2Cu3O7-x thin-film electrodes of bicrystal Josephson junctions with chemical and thermal treatments of substrates

 

I. I. Gundareva 1,2, V. N. Gubankov 1, Y. Divin 1,2

1Kotelínikov Institute of Radio Engineering and Electronics of Russian Academy of Sciences

2Peter Grünberg Institute, Forschungszentrum Jülich, Jülich, Germany

 Received March 20, 2013 

Abstract. Effects of technological parameters on electrical and structural properties of epitaxial YBa2Cu3O7-x thin films have been studied. The YBa2Cu3O7-x thin films were fabricated by dc sputtering and intended to be used as base electrodes of Josephson junctions.† The parameters of chemical and thermal treatments of NdGaO3 substrates were found, which guarantee the high, up to 5106ņ/Ům2 at the temperature of 78K, values of the critical current densities for the c-axis YBa2Cu3O7-x thin films with the widths of a few micrometers. In the case of the YBa2Cu3O7-x films with tilted c-axes, the critical current density in the direction of the tilt decreased with a decrease of the film width and in perpendicular direction reached the values up 1.3107ņ/Ůž2.† Voltage-current characteristics of the YBa2Cu3O7-x films above the critical currents Ic were found to be good described by an equation V = a(I - IŮ)b, where the b-indexes were ranging from 2 to 3 depending on the c-axis tilt †and the temperature of substrate annealing in oxygen.

Keywords: high temperature superconductivity, epitaxial thin films, Josephson junctions.