Artificial flux pinning centers in large, single-grain (RE)-Ba-Cu-O superconductors

Abstract

Non-destructive magneto-strain analysis of YB2Cu3Oy superconducting magnets using neutron diffraction in the time-of-flight mode J. Appl. Phys. 112, 063923 (2012) Thermoelectric properties of YBa2Cu3O7−δ-La2/3Ca1/3MnO3 superlattices Appl. Phys. Lett. 101, 131603 (2012) Analog of the susceptibility spectrum for levitation forces between a superconductor and a permanent magnet J. Appl. Phys. 112, 033908 (2012) Effect of thermal inhomogeneity for terahertz radiation from intrinsic Josephson junction stacks of Bi2Sr2CaCu2O8+δ Appl. Phys. Lett. 100, 242603 (2012) Recycling failed bulk YBCO superconductors using the NdBCO/YBCO/MgO film-seeded top-seeded melt growth method Second-phase, nanoscale inclusions of composition Y 2 Ba 4 CuM O y (M ϭU, Nb, Ta, W, Mo, and Re͒, which form artificial pinning centers, have been introduced into large, single-grain ͓rare-earth ͑RE͔͒-Ba-Cu-O superconductors. A significant improvement in critical current density is observed in these samples, due presumably to various combinations of normal conducting, paramagnetic, and geometrical properties of the Y 2 Ba 4 CuM O y particles in the superconducting (RE͒Ba 2 Cu 3 O 7Ϫ␦ ͑RE-123͒ phase matrix. These Y 2 Ba 4 CuM O y phase particles are chemically stable in the Ba-Cu-O liquid during peritectic solidification, unlike Y 2 BaCuO 5 ͑Y-211͒ phase particles in Y-Ba-Cu-O, which opens a processing window for the fabrication of nanostructured large, single-grain ͑RE͒-Ba-Cu-O superconductors with enhanced flux pinning for high-field engineering applications.

Real-Time Observation of Growth and Orientation of Sm−Ba−Cu−O Phases on a Sm-211 Whisker Substrate by High-Temperature Optical Microscopy

“…The preferential orientation of Y-211 in the Y-123 matrix was discussed by Endo et al For melt-textured Y-123 bulks, it is considered that properly distributed flux pinning sites are more effective in pinning enhancement than randomly distributed ones. Such an effect was demonstrated by Cardwell et al, who distributed small Y 2 Ba 4 MCuO y particles in a Y-123 matrix. , In growing multilayers composed of alternating ultrathin Y-123 and Y-211 films by means of pulse laser deposition (PLD), a growth orientation effect of nanometer-sized Y-211 particles within the Y-123 phase was revealed: the b -axis of the Y-211 phase was parallel to the c -axis of the Y-123 phase. The small lattice mismatch between the two phases might cause the epitaxial growth orientation in the matrix.…”

“…Since the discovery of high-temperature superconductivity in RE−Ba−Cu−O (RE = rare-earth element), much effort has been devoted to improvement of fundamental properties of these compounds to enable their practical applications. − During RE−Ba−Cu−O growth, artificial pinning centers are introduced into the superconducting matrix to increase the critical current density ( J c ) in low, intermediate, and high magnetic fields . Several types of effective dopands ((RE) 2 BaCuO 5 (RE-211), BaZrO 3 , (RE) 2 Ba 4 CuMO y , etc.) have been introduced.…”

“…It has been experimentally confirmed that the size, distribution, and alignment of the dopand particles in the (RE)Ba 2 Cu 3 O y (RE-123) matrix significantly influenced the pinning effect. Magnetic performance of high- T c materials can be in particular enhanced by using nanometer-scale dopand particles or/and by refining their distribution within the material. − However, not only does the particle size matter, but also the alignment of the pinning sites should be regarded. The preferential orientation of Y-211 in the Y-123 matrix was discussed by Endo et al For melt-textured Y-123 bulks, it is considered that properly distributed flux pinning sites are more effective in pinning enhancement than randomly distributed ones.…”

Nanosized Pinning Centers in the Rare Earth-Barium-Copper-Oxide Thin-Film Superconductors

“…there can be a surplus of individual elements in the form of metal oxides or compounds which also belong to the individual REBCO system [ 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. Additional phases, designed to serve as artificial pinning centers should be stable in the deposition conditions and chemically inert in relation to other present compounds in order to improve the properties of the final coated superconducting tapes [ 53 ]. There are several techniques for REBCO thin-film synthesis.…”

Crystallographic Orientation of Y2Ba4CuMOx (M=Nb, Zr, Ag) Nanoparticles Embedded in Bulk, Melt‐Textured YBCO Studied by EBSD

“…has been identified. Nanopowders of this new phase have been prepared successfully, enabling the growth of melt‐textured bulk samples with embedded nanoparticles of these phases 10,11 . There are two basic methods by which such nanoparticles can be generated in melt‐textured YBCO: (i) by adding the respective oxides (e.g., Nb 2 O 5 ) or (ii) by adding previously prepared, fully reacted nanoparticles to the precursor powder.…”