Hindawi Publishing Corporation Advances in Condensed Matter Physics Volume 2013, Article ID 821073, 5 pages http://dx.doi.org/10.1155/2013/821073 Research Article Electrical Transport Properties of (Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3 O 10 )/Ag Tapes with Different Nanosized MgO Nabil A. A. Yahya and R. Abd-Shukor School of Applied Physics, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia Correspondence should be addressed to R. Abd-Shukor; ras@ukm.my Received 6 July 2013; Revised 4 November 2013; Accepted 4 November 2013 Academic Editor: R. N. P. Choudhary Copyright © 2013 N. A. A. Yahya and R. Abd-Shukor. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. MgO nanopowders with average size 20 and 40nm were introduced into (Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3 O 10 )(MgO) x (=0–0.15 wt.%) in the pellet form. he optimum amounts for the highest transport critical current density   were  = 0.10 and 0.01 wt.% for 20 and 40nm MgO, respectively. hese results were used to fabricate MgO added (Bi, Pb)-2223/Ag sheathed tapes using the powder-in- tube method. he tapes were sintered at 845 ∘ C for 50 h and 100 h. he structure, microstructure, and   of the tapes were determined. he temperature and magnetic ield dependence of   for the MgO added tapes exhibited a signiicant enhancement compared with the nonadded tapes.   of 20 nm MgO added tape was higher compared with the 40 nm MgO added tape. A higher   was obtained when the tapes were sintered for 100 h. he increase in   can be explained as the increase of the lux pinning strength by nanosized MgO. he nanoparticle with size closer to the coherence length was more efective in enhancing   . 1. Introduction he transport critical current density   in Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3 O 10 ((Bi, Pb)-2223) high temperature superconductor is limited by the intergrain weak links, grain alignment, and the weak pinning of lux lines [1–3]. hese factors suppressed the   and thus prevent the extensive applications of (Bi, Pb)-2223 superconductor. he weak link is also observed in silver-sheathed (Bi, Pb)-2223 tape prepared by powder-in- tube (PIT) technique [4, 5]. Nanoparticles have been used as pinning centers to improve   (e.g., [6–9]). Pinning center with size larger than the coherence length  was suggested to improve   [10]. However, other studies have suggested that the optimum size of pinning centers should be comparable to the penetration depth  rather than  [11]. he  of (Bi, Pb)-2223 system is 2.9 nm and  is 60–1000 nm. It is expected that the interaction between lux line and the nanoparticles will be strong for a particle with size  where << [12]. In previous reports, MgO nanoparticles and nanorods (with average diameter of 30 nm) have been added into (Bi,Pb)-2223/Ag tapes [13, 14]. MgO is chemically inert with (Bi, Pb)-2223, and the transition temperature   did not change considerably with MgO content. In those reports, nanosized MgO additions into (Bi, Pb)-2223/Ag tapes have only been carried out with one average size [13, 14]. It is interesting to investigate the efect of diferent nanosized MgO on the critical current density of the (Bi, Pb)-2223 system. Our initial study on samples in pellet form showed that at 77 K, Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3 O 10 (MgO) x (=0–0.15 wt.%) pellets exhibited the highest   at  = 0.10 wt.% for 20 nm MgO and  = 0.01 wt.% for 40 nm MgO. It is interesting to study the efect of the two diferent nanosized MgO with those amounts in (Bi, Pb)-2223(MgO) x /Ag tapes. In this paper, we report on the efect of 20 nm ( = 0.1 wt.%) and 40 nm ( = 0.01 wt.%) MgO in (Bi, Pb)-2223(MgO) x /Ag tapes. We also report the inluence of sintering time (50 and 100 h) on   . 2. Experimental Details Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3 O 10 superconductor was prepared by the acetate coprecipitation technique. he powders were calcined at 730 ∘ C for 12 h. Followed by calcination at 845 ∘ C for 24 h.