Table of Contents
International Journal of Superconductivity
Volume 2014 (2014), Article ID 317974, 9 pages
http://dx.doi.org/10.1155/2014/317974
Research Article

The Stratified Superconductivity in Ba0.6K0.4BiO3 Single Crystal: Direct Measurement of Energy Gap between Homo-, and Inhomogeneous States

1P.N. Lebedev Physical Institute of the RAS, Moscow 119991, Russia
2Institute of Solid State Physics RAS, Chernogolovka 142432, Russia
3L.V. Kirensky Institute of Physics, Siberian Branch of RAS, Krasnoyarsk 660036, Russia

Received 30 September 2013; Revised 18 December 2013; Accepted 19 December 2013; Published 2 March 2014

Academic Editor: Zigang Deng

Copyright © 2014 L. N. Zherikhina et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The existence of space inhomogeneous superconductor insulator state (SISIS) found out earlier in polycrystalline samples of high- system ( K) is confirmed on single crystal. At ( K) the transition from the homogeneous superconducting state into the SISIS occurs. SISIS is characterized by the appearance of two gaps on the Fermi surface, semi- and superconducting, which are modulated in space in antiphase, the electric transport between superconducting regions being carried out due to Josephson tunneling. Thus the whole sample becomes a multiple Josephson system. Nonlinear curves are observed on single crystal at temperatures below . Dependence of curves on temperature and magnetic field, typical to a Josephson system, was found out. Besides, a step-like peculiarity at the values of voltage of the order of one and two superconducting gaps shows up. These peculiarities are suppressed by magnetic field much earlier than critical current. The new data firstly correlate with the model of SISIS and secondly permit for the first time to determining directly the energy gap between homogeneous and stratified superconductor states.