Mixed order parameter symmetries in cuprate superconductors

The recent observation of an inflection point in the temperature dependence of the in-plane magnetic field dependence (lambda_ab) is investigated within a two-band model with coupled order parameters of different symmetries. While the dominant order parameter has d-wave symmetry, the smaller one is of s-wave symmetry. Superconductivity is robust in the d-wave channel and induced via interband interactions in the s-wave subsystem.Comment: 10 pages, 4 figure

Properties of Electrochromic Cell with WO3 and NiO: the Influence of Ionic Conductor

The electrochromic WO3 and NiO films were deposited by magnetron sputtering on indium tin oxides coated glass. The structural properties of the films were investigated by scanning electron microscopy and X-ray diffractometery techniques. The electrochromic properties of the films were investigated by means cyclic voltammetry using different types of ionic conductors. The use of water electrolytes and electrolytes which are based on propylene carbonate leads to the destruction of electrochromic cells. The stable working electrochromic cell with WO3 and NiO films was obtained using ionic liquid as the ionic conductor. The coloration efficiency of electrochromic cell which is based on amorphous WO3 film and crystalline NiO film is 28.7 cm2 /C. Keywords: tungsten oxide, nickel oxide, electrochromic cell, ion conductor

Evidence of s-wave subdominant order parameter in YBa(2)Cu(3)O(7-delta) from break-junction tunneling spectra

The tunneling spectra of YBa(2)Cu(3)O(7-delta) break junctions have been investigated for tunneling close to the node direction. The behavior of the zero-bias conductance peak (ZBCP) and the Josephson current have been studied as a function of the temperature and magnetic field. The deep splitting of the ZBCP is observed starting at T(S)< 20-30 K in agreement with the d(x)(2)-y(2)+/- is order parameter theory [Y. Tanuma, Y. Tanaka, S. Kashiwaya, Phys. Rev. B 64, 214519 (2001)]. We have observed that a low (0.04 T) magnetic field significantly suppresses such splitting. The 1/T temperature dependence of the maximum Josephson current going to saturation at T < T(S) also confirms mixed order parameter formation

Development of Criteria for Analysis of Point-contact Sensor Characteristics in Complex Gas Media

Abstract The electric conductivity of point-contact multistructured sensors in a complex medium of the human breath gas has been studied. Considering a large number of parameters which characterize response curves of point-contact sensors, we proved the possibility of using a statistical procedure to assess the reproducibility of sensor operation. To select sensors with similar parameters from a studied set of sensors, the method of cluster analysis was employed. As a result, we first propose a criterion for selection of uniform sensors from sample sets based on sensing arrays, each containing over 200 point-contact sensing elements. We demonstrate the effectiveness of the proposed approach for the selection of uniform sensors in experiments with breath gas exhaled by a volunteer. In this case, pairs of random elements from the formed cluster show a good reproducibility of their sensor images. The selected elements are thus proved to be uniform samples which can be used to study complex gas media, for example, in clinical practice to develop methods of noninvasive diagnosis based on breath analysis