A comparative review of physical properties in the hydrated cobaltate superconductor

Research results in recent years with regard to the hydrated cobaltate superconductor have been reviewed and outlined below to compare their experimental data in them with theoretical ones, which have been discussed for several years based on unconventional superconductors. In this review, the two types of upper critical field data are cited, one exceeding the Pauli limit at x = 0.30 and the other not exceeding it at x = 0.35. As is well known, inclusion of the f-wave triplet state, doped canting spin structure in it suggested in the SBP model, breaking inversion symmetry and spin-orbit coupling, which are major candidates to interpret experimental data, are introduced to hint physical properties of this group of superconductors to satisfy a contradiction in this system though there are some problems in this review thyat requires further reviews. (C) 2010 Elsevier B.V. All rights reserved.