Dopant effects on the superconductivity of YBa2Cu3O7 ceramics

摘要: We investigated the effects of SrTiO3 and 17 different oxide dopants, namely Ca, Sc, La, Zr with possible substitution in yttrium sites, K, Sr, Pb barium Li, Mg, Fe, Co, Ni, Zn, Al, Ti, Nb, Si copper sites on superconductivity YBa2Cu3O7. These dopants can be classified into four categories depending their solubilities cation sublattices YBa2Cu3O7 perovskite. Dopants first category dissolve substitute sublattice they significantly reduce transition temperature For example, three this category, at 2 mole % dopant level, temperatures to 66, 65, 82 respectively. The second these e.g., Sr concentration, do not have any significant effect While AlO1.5 SiO2, third a limited solubility YBa2Cu3O7, strong tendency decompose superconducting phase by leaching out some components undecomposed remains unaffected ∼91 K even though susceptibility signal is reduced substantially. Since fourth very little reactivity are present simply as an inert among matrix.