Magneto-optic and magnetic properties of (Nd0.33Eu0.33Sm0.33)(1-x)YxBa2Cu3Oy superconductors

Among the light rare earth (LRE)Ba2Cu3Oy (LRE elements: Nd, Sm, Eu and Gd) family, in which LRE site is compounded with three different elements, only (Nd0.33Eu0.33Sm0.33)Ba2Cu3Oy (NES123) exhibits poor nux pinning properties along with a broad superconducting transition. However, when Y is added to NES123, the sample exhibits high J(c) values and a sharp superconducting t ransition T-c. The flux distribution of NES123 with magneto-optical (MO) ob servations revealed that the NES123 sample is not a single domain, while th e Y added NES123 exhibits single grain feature. Thus, poor superconducting properties are not inherent to the NES123 system and dependent on processin g conditions. In fact, the superconducting properties of NSE123 were dramat ically improved by using melt-quenched powders as precursor. The J(c)(B) cu rves derived from magnetization loops exhibited a strongly developed peak e ffect fur the melt-quenched NSE123. (C) 3000 Elsevier Science B.V. All righ ts reserved.