Ž . Physica C 338 2000 284–290 www.elsevier.nlrlocaterphysc Magneto-optic and magnetic properties of ž / Nd Eu Sm Y Ba Cu O superconductors 0.33 0.33 0.33 1yx x 2 3 y A. Das a,b, ) , M. Muralidhar b , M.R. Koblischka b , M. Murakami b a Laboratorium Õoor Vaste Stoffysica en Magnetisme, Katholieke UniÕersiteit LeuÕen, Celestijnenlaan 200D, B-3001, LeuÕen, Belgium b SuperconductiÕity Research Laboratory, International SuperconductiÕity Technology Center, 1-16-25, Shibaura, Minato-Ku, Tokyo, 105 0023, Japan Received 26 January 2000; received in revised form 5 April 2000; accepted 10 April 2000 Abstract Ž . Ž . Among the light rare earth LRE Ba Cu O LRE elements: Nd, Sm, Eu and Gd family, in which LRE site is 2 3 y Ž . Ž . compounded with three different elements, only Nd Eu Sm Ba Cu O NES123 exhibits poor flux pinning 0.33 0.33 0.33 2 3 y properties along with a broad superconducting transition. However, when Y is added to NES123, the sample exhibits high J c Ž . values and a sharp superconducting transition T . The flux distribution of NES123 with magneto-optical MO observations c revealed that the NES123 sample is not a single domain, while the Y added NES123 exhibits single grain feature. Thus, poor superconducting properties are not inherent to the NES123 system and dependent on processing conditions. In fact, the superconducting properties of NSE123 were dramatically improved by using melt-quenched powders as precursor. The Ž . J B curves derived from magnetization loops exhibited a strongly developed peak effect for the melt-quenched NSE123. c q 2000 Elsevier Science B.V. All rights reserved. PACS: 74.60 Ec; 74.60 Ge; 74.60 Jg Ž . Keywords: Ternary superconductors; Nd; Sm; Eu; MO imaging; Meltquenching; J B scaling c 1. Introduction Advances in melt processing techniques enabled the production of large grain RE–Ba–Cu–O with Ž . large critical current density J values superior to c ) Corresponding author. Laboratorium voor Vaste Stoffysica en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium. Tel.: q 32-16-327-203; fax: q 32-16-327-983. Ž . E-mail address: arabinda.das@fys.kuleuven.ac.be A. Das . 3 = 10 8 Arm 2 at 77 K. This has opened up new wx vistas for bulk applications 1 . Particularly the light Ž . Ž rare earth LRE Ba Cu O where LRE denotes Nd, 2 3 y . Eu, Sm and Gd superconductors processed in a w reduced oxygen atmosphere oxygen controlled melt Ž .x growth OCMG exhibit a very sharp superconduct- ing transition with T of 95 K and high J values c c even at 77 K and fields higher than 2 T. These systems have a LRE Ba Cu O type solid solu- 1qx 2yx 3 y tion. The substitution of trivalent LRE for divalent Ba is dependent on the oxygen partial pressure dur- ing the melt process, so that a change in the process- Ž . wx ing parameters affects the J B curves 2 . c 0921-4534r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. Ž . PII: S0921-4534 00 00306-3