Hybrid Approach for Studying Defects and Electronic Properties : Cuprates and MgB2 Superconductors

Systematic studies of thermophysical properties of alloyed 123 structure high Tc superconductors are required due to an increasing number of applications of these compounds rather than pure YBCO to improve bulk and grain boundary transport and other properties. Hybrid approach is developed to study lattice statics and dynamics, strain effect, elasticity, thermal expansion, congruent melting, charge transfer, chain oxygen order disorder transition, defect, space charge, and strain field in 123-cuprate. Besides, electronic structure, structure factors, and X ray absorption spectrum of MgB2 are studied by first principles method. These studies suggest that the electronic structure of MgB2 is highly anisotopic which is the origin of the multi superconducting gaps in this material.