BYZO Nanopancakes in HTS YBa2Cu3O7-δ Films: Effect on Critical Current Density and Nonlinear Microwave Response

2011 ◽  
Vol 1367 ◽  
Author(s):  
Victor S. Flis ◽  
Vassily L. Svetchnikov ◽  
Oleksa A. Kalenyuk ◽  
Alexander L. Kasatkin ◽  
Viacheslav O. Moskaliuk ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Current Density ◽  
Flux Pinning ◽  
Electric Transport ◽  
Microwave Response ◽  
Pinning Centers ◽  
Thermally Activated ◽  
Different Types ◽  
Substrate Temperatures ◽  
Elastic Strains

ABSTRACTWe have studied nanostructure, electric transport and microwave properties of HTS YBa2Cu3O7-δ films prepared by PLD on LaAlO3 single crystal substrates using targets doped with BaZrO3. Two essentially different types of nanoparticles are revealed by HREM: “nanopancakes” and “nanorods”. Tiny nanopancakes are 1-4 nm in ab-plane and only few atomic layers thick. Nanopancakes are surrounded with deformed area and numerous dislocations. Such nanoparticles seem to be responsible for jc enhancement. Nanopancakes evolve to much wider and longer nanorods at higher substrate temperatures and/or slower deposition. There are no dislocations around nanorods. Elastic strains are avoided due to slight inclination of the c-axis. Dislocations around nanopancakes are suggested to be additional flux pinning centers and retard thermally activated relaxation of the dislocation nanostructure.

Transport Critical Current Density and Flux Pinning Enhancement in Nano-Sized PbO and HfO2 Added (Bi1.6Pb0.4)Sr2Ca2Cu3O10 Superconductor

2015 ◽  
Vol 1108 ◽  
pp. 85-90
Author(s):  
Nabil A.A. Yahya ◽  
R. Abd-Shukor
Keyword(s):  
Particle Size ◽  
Transition Temperature ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
Homogeneous Distribution ◽  
Transport Critical Current Density ◽  
Superconducting Properties ◽  
Pinning Centers

A comparative study on the effect of PbO (10-30 nm) and HfO2 (60-80 nm) additions on the superconducting properties of (Bi1.6Pb0.4)Sr2Ca2Cu3O10 ((Bi,Pb)-2223) superconductor in the bulk form was carried out. The structure and the microstructure of prepared samples were examined by powder XRD and SEM, respectively. The transition temperature Tc and critical current density Jc was determined by standard dc four-probe method. SEM micrographs showed a homogeneous distribution of Pb and Hf in the samples. It was observed that PbO and HfO2 additions enhanced Jc for all added samples. Jc was the highest for x= 0.05 wt. % of PbO (1130 mA/cm2 at 77 K and 1930 mA/cm2 at 30 K) and HfO2 (900 mA/cm2 at 77 K and 1760 mA/cm2 at 30 K) addition. This study showed that the addition of PbO and HfO2 nanopowder provided extra flux pinning centers in the (Bi, Pb)-2223. PbO with smaller particle size showed higher Jc compared with HfO2 which has a larger particle size.

scholarly journals Effect of Nanosized NiF2Addition on the Transport Critical Current Density of Ag-Sheathed (Bi1.6Pb0.4)Sr2Ca2Cu3O10Superconductor Tapes

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
M. Hafiz ◽  
R. Abd-Shukor
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
Flux Line ◽  
Transport Critical Current Density ◽  
Pinning Centers ◽  
Sintering Time ◽  
Line Network ◽  
Powder In Tube

We report the effect of NiF2(10 nm) additions on the transport critical current density,Jcof (Bi1.6Pb0.4)Sr2Ca2Cu3O10/Ag sheathed superconductor tapes. Pellets of (Bi1.6Pb0.4)Sr2Ca2Cu3O10(NiF2)x(x=0–0.05 wt.%) superconductor were prepared using the acetate coprecipitation method. The sample with 0.04 wt.% addition of NiF2exhibited the highestJc. Ag-sheathed (Bi1.6Pb0.4)Sr2Ca2Cu3O10(NiF2)0.04superconductor tapes were fabricated using the powder-in-tube (PIT) method and sintered at 845°C for 50 and 100 h.Jcof nonadded tapes at 30 K sintered for 50 and 100 h was 6370 and 8280 A/cm2, respectively.Jcof (Bi1.6Pb0.4)Sr2Ca2Cu3O10(NiF2)0.04/Ag tape at 30 K sintered for 50 and 100 h was 14390 and 17270 A/cm2, respectively. In magnetic fields (0 to 0.7 T),Jcof the NiF2added tapes was also higher compared with the nonadded tape indicating that NiF2nanoparticles can act as effective flux pinning centers and longer sintering time improved the microstructure. A steeper increase inJcwas observed below 60 K in the NiF2added tapes which coincided with the Neel temperature,TNof nanosized NiF2(60 K). The pronounced enhancement ofJcwas attributed to the strong interaction between flux line network and the antiferromagnetic NiF2belowTN.

Critical current density and flux pinning in Gd1−xYxBa2Cu3O7−y epitaxial thin films

1995 ◽  
Vol 250 (1-2) ◽  
pp. 55-58 ◽  
Author(s):  
R.L. Wang ◽  
H.C. Li ◽  
B. Yin ◽  
J.W. Li ◽  
X.S. Ron ◽  
...  
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
Epitaxial Thin Films

Enhancement of flux pinning and high-field critical current density in carbon-alloyedMgB2thin films

2006 ◽  
Vol 74 (17) ◽  
Author(s):  
J. Chen ◽  
V. Ferrando ◽  
P. Orgiani ◽  
A. V. Pogrebnyakov ◽  
R. H. T. Wilke ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
High Field

STABILIZATION OF Bi(2223) SUPERCONDUCTING PHASE BY VANADIUM OXIDE ADDITION

1993 ◽  
Vol 07 (01n03) ◽  
pp. 157-161 ◽  
Author(s):  
D. SURESH BABU ◽  
G. NARSING RAO ◽  
L. BROHAN ◽  
M. GANNE
Keyword(s):  
Critical Current Density ◽  
Current Density ◽  
Flux Pinning ◽  
Volume Fraction ◽  
Ac Susceptibility ◽  
Superconducting Phase ◽  
Nominal Composition ◽  
Oxide Addition ◽  
Probable Role

We report on the ac susceptibility, microwave absorption and dc magnetization of Bi 2− x V x Sr 2 Ca 2 Cu 3 O y (nominal composition). The low T c (2212) phase ( T c = 85 K ) dominates in the x = 0 sample with extremly weak flux pinning. In x = 0.4 sample, both flux pinning and volume fraction of the high T c (2223) phase ( T c = 105 K ) were increased. The intragrain critical current density of the sample with x = 0.4 was estimated and found to be comparable with that of Pb doped Bi 2 Sr 2 Ca 2 Cu 3 O y superconductor. The data suggest that addition of V 2 O 5 in Bi 2 Sr 2 Ca 2 Cu 3 O y system increases the volume fraction of the high T c phase. Probable role of vanadium in enhancing the high T c (2223) phase in Bi-V-Sr-Ca-Cu-O system is discussed.

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