Synthesis of Unidirectionally Solidified Y‐Ba‐Cu‐0 Bulk Superconductors with High Critical Current Densities

1989 ◽  
Vol 169 ◽  
Author(s):  
E. Yanagisawa ◽  
S. Kondoh ◽  
J. Shimoyama ◽  
J. Kase ◽  
T. Matsubara ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Current ◽  
Applied Magnetic Field ◽  
Bulk Materials ◽  
Large Plate ◽  
Bulk Superconductors ◽  
Plate Shape ◽  
Current Densities ◽  
Melt Solidification

Abstract(Y,Ho)‐Ba‐Cu‐0 superconductors with the high critical current densities (Jc) in an applied magnetic field have been synthesized by a unidirectional melt solidification method. Melt solidified bulk materials are composed of large plate‐shape (Y,Ho)Ba2Cu3Oy crystals which contain small (∼5 um) particles of (Y.Ho)2BaCuO5. The Jc value of the melt solidified (Y,Ho)‐Ba‐Cu‐0 sample is ∼10000 A/cm2 at 77K, H = IT and this value is much higher than the value of 4200 A/cm2 of the melt solidified Y‐Ba‐Cu‐O sample.

Structure and Functional Properties of Bulk MgB2 Superconductors Synthesized and Sintered under Pressure

2014 ◽  
Vol 792 ◽  
pp. 21-26 ◽  
Author(s):  
Tatiana Prikhna ◽  
Michael Eisterer ◽  
Wolfgang Gawalek ◽  
Athanasios G. Mamalis ◽  
Artem Kozyrev ◽  
...  
Keyword(s):  
Critical Current ◽  
Material Structure ◽  
Bulk Materials ◽  
Critical Fields ◽  
Current Densities ◽  
Upper Critical Fields ◽  
Irreversibility Fields ◽  
Grain Boundary Pinning ◽  
Effect Of Oxygen ◽  
Oxygen Impurities

The high pressure (50 MPa - 2 GPa) – high temperature synthesized MgB2 bulk materials are characterized by nearly theoretical density (1-2% porosity), 80-98% connectivity, extremely high critical current densities (e.g. at 20 K, in 0–1 T jc=1.3–1.0 MA·cm-2 (with 10% SiC) and jc= 0.92 – 0.73 MA·cm-2 (without doping)), large irreversibility fields (Birr(18.4 K) =15 T and Birr (0 K) = 32.5 T) and high upper critical fields (Bc2 (22 K) =15 T and Bc2(0 K) ~ 42.1 T). The transformation of grain boundary pinning to point pinning in MgB2-based materials with increasing manufacturing temperature (from 800 to 1050 oC) under pressures from 0.1 to 2 GPa correlates well with an increase in critical current density in low external magnetic fields caused by the redistribution of boron and the oxygen impurities in the material structure. As the manufacturing temperature increases, the discontinuous oxygen enriched layers transform into distinct Mg-B-O inclusions and the size and amount of inclusions of higher magnesium borides MgBX (X>4) are reduced. The effect of oxygen and boron redistribution can be enhanced by Ti or SiC additions.

Composition Effects on the Critical Current of MOCVD-Processed Zr:GdYBCO Coated Conductors in an Applied Magnetic Field

2011 ◽  
Vol 21 (3) ◽  
pp. 3166-3170 ◽  
Author(s):  
Yimin Chen ◽  
Tuo Shi ◽  
Albert P. Guevara ◽  
Yangxin Zhang ◽  
Yao Yao ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Current ◽  
Applied Magnetic Field ◽  
Coated Conductors ◽  
Composition Effects

YBCO Bulk Superconductors with Sm Addition

2017 ◽  
Vol 891 ◽  
pp. 483-488 ◽  
Author(s):  
Daniela Volochová ◽  
Vitaliy Antal ◽  
Jozef Kováč ◽  
Pavel Diko
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Superconducting Properties ◽  
Ybco Bulk ◽  
Pinning Centers ◽  
Bulk Superconductors ◽  
Powder Addition ◽  
Current Densities ◽  
Precursor Powders

The influence of Sm addition on the microstructure and superconducting properties of Y-Ba-Cu-O (YBCO) bulk superconductors has been studied. Precursor powders YBa2Cu3O7-δ (Y-123), Y2O3 and CeO2 were enriched with different amounts of SmBa2Cu3Oy (Sm-123) or Sm2O3 powders with the aim to increase critical current density, Jc,by introducing additional pinning centers. YBCO bulk superconductors with SmBa2Cu3Oy (Y123-Sm) or Sm2O3 (Y123-SmO) powder addition were prepared by the optimized top seeded melt growth process in the form of single grains. Microstructure analysis revealed that Sm2O3 addition leads to a higher amount of smaller Y2BaCuO5 (Y-211) particles, what is related to high critical current densities (Jc ~ 7 x 104 A/cm2) of the YBCO samples with Sm2O3 addition in low magnetic fields. The effect of Sm addition in the form of SmBa2Cu3Oy as well as Sm2O3 powder on Y2BaCuO5 particle size, critical temperature, Tc, and critical current density, Jc, is reported.

Transport Measurements on Superconducting YBa2Cu3O7-δ Thin Film Lines

1989 ◽  
Vol 169 ◽  
Author(s):  
B. H. Moeckly ◽  
D. K. Lathrop ◽  
G. F. Redinbo ◽  
S. E. Russek ◽  
R. A. Buhrman
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Critical Current ◽  
Weak Link ◽  
High Sensitivity ◽  
Weak Links ◽  
Microwave Response ◽  
Field Response ◽  
Current Densities ◽  
Iv Curves

AbstractCritical current densities, magnetic field response, and microwave response have been measured for laser ablated YBa2Cu3O7-δ thin film lines on MgO and SrTiO3 substrates. Films on SrTiO3 have critical current densities > 1 x 106 A/cm2 at 77K and show uniform transport properties in lines of all sizes. Films on MgO have critical current densities which range between 102 and 106 A/cm2 at 77K and show considerable variation from device to device on the same chip. Narrow lines on MgO with low critical current densities show Josephson weak link structure which includes RSJ-like IV curves, microwave induced constant voltage steps, and a high sensitivity to magnetic field. The presence of the Josephson weak links is correlated with small amounts of misaligned grains in films on MgO.

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