Transmission electron microscopy studies of YBCO coated conductors prepared by pulsed-laser deposition and multiple-stage chemical vapor deposition processes

High-rate deposition of YBa2Cu3O7−δhigh-temperature superconducting films by IR-laser-assisted chemical vapor deposition

“…The differences in the origins of the nucleation and thickness effects on the amount of a-axis grains, that is, an increasing trend with increasing thickness, should be recognized. The primary origin of the nucleation is considered to be a kinetic limitation of the deposits in the former case [46,34] and outgrowth of the second phases in the matrix in the latter case [39,47,42,36]. The strain effect due to the lattice mismatch with the substrate [40] is not likely to be the main cause because the a-axis nucleation is not as sharp a transition with respect to the thickness in this study and seems to be widely observed irrespective of the substrate materials.…”

“…Figure 3 shows SEM surface images of these samples. The a-axis-oriented grains are identified as needle-like or rectangular objects [34][35][36][37][38][39] in the micrographs. As a result of faster growth of YBCO along the a axis than along the c axis, a rectangular (or needle-like) shape, the long axis of which corresponded to the crystallographic a-axis, was formed [40][41][42].…”

“…To achieve high J c values, it is necessary to eliminate the a-axis-oriented grains because of their poor (or deleterious influence on the) current-carrying capacities of the film. Generally, a-axis-oriented grains tend to emerge in thick films, probably because of either deviations in the growth conditions [46,34] or overgrowth of a-axis grains nucleated from second phases such as Cu-O or YBa 3 Cu 2 O x [39,47,42,36]. The differences in the origins of the nucleation and thickness effects on the amount of a-axis grains, that is, an increasing trend with increasing thickness, should be recognized.…”

Moiré Fringe Analysis of BaZrO3 Nanorods in ErBa2Cu3O7-δ Films

“…Recently, many researchers have attempted to distribute nanosized compounds as artificial pinning centers (APCs) in a superconductive layer. [4][5][6][7][8][9] High-crystalline-quality RE-BCO (RE: rare-earth elements) thin films and BZO-doped REBCO thin films have low surface resistances. [7][8][9] Goyal et al 5) reported the structure of BZO nanodots in an YBCO film, in which the resultant BZO nanodots were aligned along the crystallographic c-direction in YBCO and were about 2 -3 nm in diameter.…”

“…[4][5][6][7][8][9] High-crystalline-quality RE-BCO (RE: rare-earth elements) thin films and BZO-doped REBCO thin films have low surface resistances. [7][8][9] Goyal et al 5) reported the structure of BZO nanodots in an YBCO film, in which the resultant BZO nanodots were aligned along the crystallographic c-direction in YBCO and were about 2 -3 nm in diameter. Kato et al 9) reported the orientation relationship between YBCO and BZO as (001) YBCO k (001) BZO and (100) YBCO k (100) BZO, then BZO are imaged using Moire ´fringes.…”