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Pellet‐buffered film seed to grow single grain bulk YBCO
Author(s) -
Yang ChiaMing,
Liu ChiaHao,
Chen BoXiani,
Chang ChinWei,
Chen InGann
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15050
Subject(s) - materials science , nucleation , pellet , layer (electronics) , substrate (aquarium) , epitaxy , buffer (optical fiber) , diffusion , composite material , grain size , thin film , phase (matter) , chemical engineering , nanotechnology , chemistry , oceanography , physics , organic chemistry , engineering , thermodynamics , geology , telecommunications , computer science
Epitaxial thin film seeds, exhibit a higher peritectic temperature than the bulk, have been recognized as a possible way to obtain large‐sized single‐grain REBCO bulks. Recently, use of a pellet as a buffer layer inserted between the film‐seed and the main pellet has been reported. This approach can prevent Mg diffusion from the MgO substrate to the film seed, and enable the thin film to tolerate a higher maximum temperature in the TSMG (Top Seed Melt Growth) method. However, we found that the liquid phase decomposed from YB a 2 Cu 3 O 7− x ( YBCO ) contacted the MgO substrate, due to surface tension, and caused undesirable grain nucleation. To resolve this problem, this study used a mini‐pellet, smaller than the seed, as a buffer layer. This new technique can avoid the liquid phase contacting the MgO substrate, thereby allowing the YBCO single‐grain bulk to be grown more easily. Moreover, the thin film seed can be re‐used by removing the buffer layer after the crystal growing process.