In order to fabricate long-length high temperature superconducting coated conductors, we have employed a batch-type reactive co-evaporation process for the deposition of a SmBCO layer on the IBAD-MgO substrate of LaMnO 3 /epi-MgO/IBAD-MgO/Y 2 O 3 /Al 2 O 3 /Hastelloy. Critical current densities (J c ) of SmBCO coated conductors were investigated with respect to their composition ratios. Higher J c was obtained in the Sm-rich, Ba-poor and Cu-rich composition region, compared to the stoichiometric region. The highest critical transition temperature (T c ) of the SmBCO coated conductor was ∼94 K with a narrower transition width of about 0.5 K. A 93 m long SmBCO layer was deposited on a 4 mm wide IBAD-MgO substrate for 90 min. Although some differences in the appearance of pores and Cu oxide precipitates between both ends of the deposited tape exist, the deposited SmBCO layer was dense and biaxially textured. The growth of a highly textured SmBCO layer was maintained up to the thickness of 2.2 μm. A minimum I c of 305 A/cm-w was achieved at the 27 m section of the 93 m long SmBCO coated conductor at 77 K in self-field.
This paper reviews recent progress in research and development (R&D) of reactive co-evaporation for high performance REBCO coated conductors in Korea. Two types of reactive co-evaporation methods were developed for the deposition of SmBCO and GdBCO superconducting layers respectively on the IBAD (Ion Beam Assisted Deposition)-MgO template in the Korean coated conductor project. Batch type reactive co-evaporation equipment and its processing were developed for SmBCO coated conductors at Korea Electrotechnology Research Institute (KERI) in conjunction with the Korea Advanced Institute of Science and Technology (KAIST), and a very high critical current exceeding 1,000 A/cm at 77 K in the self field was achieved through the optimization of deposition parameters. Reel-to-reel type reactive co-evaporation processing with a high conversion rate was also developed, while long length GdBCO coated conductors have been routinely produced by SuNAM Co. The minimum critical current of 422 A/cm-w at 77 K in self field was confirmed for 1 km-long GdBCO tape.
We present the anisotropy of current transport characteristics in Bi-2223/Ag multifilamentary tapes as a function of temperature and external magnetic field. Angular dependence of the critical current and the glass-liquid transition magnetic flux density are well described by the model, taking into account the misorientation of grains with constant effective anisotropy factor, γ . Furthermore, γ increases apparently as temperature and/or critical current increases due to the weak-link properties.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.