Pinning Performance of (Nd_0.33Eu_0.2Gd_0.47)Ba₂Cu₃O_y Single Crystal

M. Jirsa¹, M. Rames¹, P. Das², M. R. Koblischka², T. Wolf3, U. Hartmann^2
1 Institute of Physics ASCR, Na Slovance 2, CZ-182 21 Prague 8, Czech Republic;               
e-mail: jirsa@fzu.cz
² Institute of Experimental Physics, Saarland University, D-66041 Saarbrücken, Germany
³ Forschungszentrum Karlsruhe, Institute of Solid State Physics, D-76021 Karlsruhe, Germany

Abstract - The critical current density J_c, the pinning force density F(=BJ_c), and the relaxation rate Q weredetermined from magnetic hysteresis loops (MHL) measured from 65 K to 90 K on a twinned (Nd_0.33Eu_0.2Gd_0.47)Ba₂Cu₃O_y single crystal with a strip-like surface structure. The strong second peak observed on the MHL at 65 K continuously decreased with increasing temperature but persisted up to 84 K. None of the J_c(B) and F(B) dependences scaled, let alone in a narrow range of T. A strong effect of twin channeling was observed but no special pinning effect due to the strip-like surface structure was recognized.

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Manuscript received November 29, 2007; accepted Dec.19, 2007. Reference No. ST13, Category 2
Paper submitted to Proceedings of EUCAS 2007; published in JPCS 98 (2008), paper # 012191