[iopmath latex="${\bi J}_{\bi c}-{\bi B}$"] J_c-B [/iopmath] performance study of an OCMG (Nd-Eu-Gd)-123 material doped by sub-micrometre Gd-211 particles

Authors: Jirsa M.¹; Muralidhar M.²; Murakami M.²; Noto K.³; Nishizaki T.⁴; Kobayashi N.⁴

Source: Superconductor Science and Technology, Volume 14, Number 1, 2001 , pp. 50-57(8)

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Abstract:

A concentration profile of Gd₂BaCuO₅ (Gd-211) fine particles embedded in an oxygen-controlled melt-grown (Nd [iopmath latex="$_{0.33}$"] _0.33 [/iopmath] Eu [iopmath latex="$_{0.33}$"] _0.33 [/iopmath] Gd [iopmath latex="$_{0.33}$"] _0.33 [/iopmath] )Ba₂Cu₃O [iopmath latex="$_{7-y}$"] _7-y [/iopmath] (NEG-123) material is studied. The secondary phase had a nominal content of 30 mol% and was refined by the addition of 0.5 mol% Pt and 1 mol% CeO₂. The main concern of this paper is devoted to the variation of the magnetic properties and Gd-211 phase distribution in a bulk NEG-123 pellet of 1.8 cm in diameter and 1 cm in height. [iopmath latex="$J_{c}(B)$"] J_c(B) [/iopmath] dependences deduced from magnetic hysteresis curves measured by SQUID were analysed with respect to the appearance of the central and second peaks. A successful fit of all the curves by an analytical function composed of two additive contributions representing the central and second peaks is reported. The separation of these two contributions revealed that the shape of the high-field part of the magnetization curves is mostly governed by the pinning mechanism(s) responsible for the second peak and no `background' from another source of pinning is involved.

Language: English

Document Type: Miscellaneous

Affiliations: 1: Institute of Physics, ASCR, CZ-182 21 Praha 8, Czech Republic 2: ISTEC/SRL, Division 3, 1-16-25 Shibaura, Minato-ku, Tokyo 105, Japan 3: Iwate University, Faculty of Engineering, 4-3-5 Ueda, Morioka, Iwate 020-08551, Japan 4: Institute for Material Research, Tohoku University, Sendai 980-77, Japan

Publication date: 2001-01-01