Preparation Of Ybco Single Domain And The Electronic Structure And The Superconducting Mechanism

Many experiments and theory researches have been made on cuprate superconductors with high-Tc, which is regarded highly and achieved much and superconductivity of cuprate is understood further. However , Tc is not high enough and there is not a systematic theory .which limit the application and development of High-Tc superconducting materials.It was systemically investigated on preparing , electronic structures and energy level feature of the high-Tc YBa2Cu307-δ superconductor. We found four features:1) The oxygen content greatly influence the energy level around the highest occupied orbit, but do little the deepest energy level, when the oxygen content increases, the energy level of the highest occupied orbit decreases, the number of orbit and the density of states near it increase, therefore critical transition temperature(Tc) will raise, it is agree with the experiment. It is important of the oxygen content for superconductivity.2) There are hybrid orbitals in energy level structures because of the interaction of atoms. The orbit energy level of atoms is closer , hybridization is higher .There are hybridization of the inner orbital between 2s orbit of 0 and 4p orbit of Y, 5p orbit of Ba . There are hybridization of the outer orbital between 3d orbit of Cu and 2p orbit of 0. Hybridization of the outer orbital was large than it of the inner orbital. There is close relation between hybrid orbital and superconductivity.It is explanation relation between hybrid orbital and superconductivity by element doping.3) The process parameters greatly effect the superconductivity of single domain YBCO. the alignment of the crystals (Cu-O plane)and the fine and uniform distribution of 211 phase particles are responsible for obtaining higher critical currents.In conclusion, according to our theory and calculation study , it is very much important for guiding our experiment in the future, it is the helpful for understanding high temperature superconductivity ,and important to the research of superconducting mechanism .