The effects of sintering temperature on superconductivity of MgB2 prepared by hot pressing

The [Formula: see text] superconductor bulks were prepared by hot-pressing under the pressure of 55 MPa at different temperatures of 650[Formula: see text]C, 700[Formula: see text]C, 800[Formula: see text]C, 900[Formula: see text]C, 1000[Formula: see text]C, respectively, and the hot-pressing effects on the superconducting properties of [Formula: see text] bulks were investigated. The density of bulk samples increased with the rise of sintering temperature and the density reached to the maximum value when the sintering temperature rose to 1000[Formula: see text]C. For the sample sintered at 1000[Formula: see text]C, the critical transition temperature ([Formula: see text] reached the highest value of 38.8 K despite the high content of [Formula: see text] (30.62 wt.%). However, the critical current density ([Formula: see text] did not increase with the increase in the density and [Formula: see text]. The sample sintered at 700[Formula: see text]C maintained the high superconducting volume and had a small grain size, thus providing the best magnetic flux pinning force and [Formula: see text]. An effective hot-pressing process to improve [Formula: see text] might be the way to prepare by further increasing the density of sintering samples at 700[Formula: see text]C.

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Effects of artificial pins on the flux pinning force and other superconducting properties in NbTi superconductors

IEEE Transactions on Applied Superconductivity ◽

10.1109/77.233646 ◽

1993 ◽

Vol 3 (1) ◽

pp. 1362-1365 ◽

Cited By ~ 19

Author(s):

K. Matsumoto ◽

Y. Tanaka ◽

K. Yamafuji ◽

K. Funaki ◽

M. Iwakuma ◽

...

Keyword(s):

Flux Pinning ◽

Pinning Force ◽

Superconducting Properties ◽

Flux Pinning Force

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TEMPERATURE SCALING OF THE FLUX PINNING FORCE FOR SmBa2Cu3O7-x SINGLE CRYSTAL

Modern Physics Letters B ◽

10.1142/s0217984905008141 ◽

2005 ◽

Vol 19 (01n02) ◽

pp. 55-58

Author(s):

L. ZHANG ◽

G. LIU ◽

X. LENG ◽

X. B. XU ◽

S. Y. DING ◽

...

Keyword(s):

Single Crystal ◽

Flux Pinning ◽

Scaling Law ◽

Force Density ◽

Pinning Force ◽

Pinning Mechanism ◽

Maximum Value ◽

Temperature Scaling ◽

Pinning Force Density ◽

Flux Pinning Force

Magnetic critical current density was measured at various temperatures and fields for SmBa 2 Cu 3 O 7-x single crystal. Pronounced second peaks were observed at intermediate fields and temperatures. Normalized pinning force density [Formula: see text] exhibited a clear scaling law when H was normalized by H max where the pinning force density has the maximum value. This is an indication that a single pinning mechanism exists in the investigated temperature region.

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Y2BaCuO5 Addition and Its Effects on Critical Currents in Large grains of YBa2Cu3O7-σ: A Quantitative Microstructural Study

MRS Proceedings ◽

10.1557/proc-411-327 ◽

1995 ◽

Vol 411 ◽

Author(s):

Manoj Chopra ◽

R. L. Meng ◽

C. W. Chu ◽

Siu-Wai Chan

Keyword(s):

Critical Current ◽

Flux Pinning ◽

Critical Currents ◽

Pinning Force ◽

Electrical Characteristics ◽

Volume Percent ◽

Initial Volume ◽

Maximum Value ◽

Melt Texturing ◽

Flux Pinning Force

ABSTRACTThe addition of Y2BaCuO5 (211) particles to large grain Yba2Cu3O7−δ (Y123) has significantly improved the critical current (Jc) in this material. Here a systematic quantitative analysis on the effect of the measured 211 present in large grains of Y123 has been performed, after the process of melt texturing, both on a microscopic and a nanoscopic scale with a systematic variation of the initial volume percent of 211 addition. From the correlation between critical current measurements and quantitative microscopy of both (001) and (110) sections, a maximum value of weighted Jc is observed corresponding to a measured Y123 volume percent of 20%. Although an increasing addition of 211 is effective in producing efficient flux pinning sites in the Y123 matrix, percolation paths in the Y123 matrix become limited for supercurrent. Accounting for the loss of liquid phase, we estimate an optimum initial volume of 211 for highest Jc to be 40%. Further correlation between the Jc and the true flux pinning force (Fp) shows a maximum pinning force for an initial 211 addition of 40%. However the pinning efficiency of the superconducting Y123 matrix is found to improve with an increasing 211 addition. Hence an optimum amount of 211 addition is essential for obtaining the best possible electrical characteristics in the superconducting composite.

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Macrosegregation of Y2Ba1Cu1O5 particles in Y1Ba2Cu3O7−δ crystals grown by an undercooling method

Journal of Materials Research ◽

10.1557/jmr.1996.0096 ◽

1996 ◽

Vol 11 (4) ◽

pp. 795-803 ◽

Cited By ~ 137

Author(s):

A. Endo ◽

H. S. Chauhan ◽

T. Egi ◽

Y. Shiohara

Keyword(s):

Growth Rate ◽

Flux Pinning ◽

Faraday Effect ◽

Growth Direction ◽

Pinning Force ◽

Garnet Film ◽

Iron Garnet ◽

Flux Pinning Force ◽

Good Agreement ◽

Iron Garnet Film

Macrosegregation of Y2Ba1Cu1O5 (Y211) particles was observed in Pt-added Y1Ba2Cu3O7−δ (Y123) crystals grown by an undercooling method. It was found that the macrosegregation of Y211 particles depended on the growth direction and the growth rate (R) as a function of undercooling (ΔT). The amount of Y211 particles in Y123 crystals grown at large R was larger than at small R. Also, the amount of Y211 in Y123 growing along the a-direction was larger than that along the c-direction. Further, it was noted that the smaller Y211 particles in size were distributed in Y123 grown at large R. These phenomena could be at least qualitatively explained by the prevalent trapping/pushing theory. In the direct observation of magnetic flux with the Faraday effect of iron garnet film, the flux pinning force was found to be in good agreement with the macrosegregation of Y211 particles.

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Effect of mechanical grinding on the transport critical current density and the flux pinning force of a YBa2Cu3OyAg composite superconductor

Journal of Alloys and Compounds ◽

10.1016/0925-8388(95)02146-9 ◽

1996 ◽

Vol 236 (1-2) ◽

pp. 165-170 ◽

Cited By ~ 2

Author(s):

Shigeru Katsuyama ◽

Yoshinao Harada ◽

Toshiyuki Tatani ◽

Yoshinori Ozawa ◽

Kazuhiko Majima ◽

...

Keyword(s):

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Flux Pinning ◽

Transport Critical Current Density ◽

Pinning Force ◽

Mechanical Grinding ◽

Composite Superconductor ◽

Flux Pinning Force

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Repulsive Flux Pinning Force in NbTi/Nb Superconductor/Superconductor Multilayers

Journal of Low Temperature Physics ◽

10.1023/b:jolt.0000044239.59812.06 ◽

2004 ◽

Vol 137 (1/2) ◽

pp. 125-137 ◽

Cited By ~ 3

Author(s):

Y. Obi ◽

M. Ikebe ◽

H. Fujishiro

Keyword(s):

Flux Pinning ◽

Pinning Force ◽

Flux Pinning Force

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Increased flux pinning force and critical current density in MgB2 by nano-La2O3 doping

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/756/1/012019 ◽

2020 ◽

Vol 756 ◽

pp. 012019

Author(s):

Danlu Zhang ◽

Fang Wan ◽

Michael D. Sumption ◽

Edward W. Collings ◽

CJ Thong ◽

...

Keyword(s):

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Flux Pinning ◽

Pinning Force ◽

Flux Pinning Force

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Pinning Force Scaling Analysis of Polycrystalline MgB2

Journal of Superconductivity and Novel Magnetism ◽

10.1007/s10948-020-05456-8 ◽

2020 ◽

Vol 33 (11) ◽

pp. 3333-3339

Author(s):

M. R. Koblischka ◽

A. Wiederhold ◽

A. Koblischka-Veneva ◽

C. Chang

Keyword(s):

Grain Boundaries ◽

Flux Pinning ◽

The Other ◽

Scaling Analysis ◽

Pinning Force ◽

Spark Plasma ◽

Force Scaling ◽

Flux Pinning Force

Abstract Flux pinning force scaling $f=F_{p}/F_{p,\max \limits }$ f = F p / F p , max vs. h = Ha/Hirr was performed on a variety of pure MgB2 samples, including a spark plasma sintered (SPS) one and a series of samples sintered at various reaction temperatures ranging between 775 and 950 ∘C. The SPS sample exhibits a well-developed scaling at all temperatures, and also the sintered samples prepared at 950 ∘C; however, the obtained peak positions of the pinning force scalings are distinctly different: The SPS sample reveals dominating pinning at grain boundaries, whereas the dominating pinning for the other one is point-pinning. All other samples studied reveal an apparent non-scaling of the pinning forces. The obtained pinning parameters are discussed in the framework of the Dew–Hughes’ pinning force scaling approach.

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