Improvement of critical current density in MgB2 superconductors by Zr doping at ambient pressure

Pulsed magnetic field was first employed in the study on MgB2 superconductors. Superconductivity properties and microstructures of Zn and SiC doped MgB2 were discussed in this paper. The superconductors showed different superconductivities after magnetic sintering. Critical current density and flux pinning force were relevant to the dopants properties in MgB2. Grains in the pulsed magnetic processed MgB2 matrix were smaller than those in the normal processed one. The refinement microstructures have caused the critical current density (Jc) anisotropy in both the Zn and SiC doped MgB2.

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Doping effect of Zr and Ti on the critical current density of MgB2 bulk superconductors prepared under ambient pressure

Physica C Superconductivity ◽

10.1016/s0921-4534(02)01395-3 ◽

2002 ◽

Vol 378-381 ◽

pp. 122-126 ◽

Cited By ~ 35

Author(s):

Y Zhao ◽

Y Feng ◽

D.X Huang ◽

T Machi ◽

C.H Cheng ◽

...

Keyword(s):

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Ambient Pressure ◽

Doping Effect ◽

Mgb2 Bulk ◽

Bulk Superconductors

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Degradation of Porosity and Enhanced Critical Current Density in MgB2 with a Toluene-Treatment Boron Powder

Materials Science Forum ◽

10.4028/www.scientific.net/msf.745-746.208 ◽

2013 ◽

Vol 745-746 ◽

pp. 208-213

Author(s):

Xi Feng Pan ◽

Guo Yan ◽

Xiang Hong Liu ◽

Yong Feng ◽

Ping Xiang Zhang ◽

...

Keyword(s):

Heat Treatment ◽

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Mass Density ◽

Ambient Pressure ◽

Treatment Temperature ◽

Porous Sample ◽

Boron Powder

A series of MgB2 bulks with different porosity have been successfully prepared by in-situ solid-state reaction at ambient pressure with a toluene-treatment boron powder. The mass density reaches 1.86 g cm-3 at the most compact MgB2 bulk, which has an imporous microstructure, excellent grains coupling, clean grain boundaries and nanosized grains (100~200 nm). Our results reveal that the porosity of MgB2 can be significantly depressed by tuning the residual toluene content and heat treatment temperature in this way. Due to the degradation of porosity and thus the enhancement on grains connectivity and grains boundary pinning, the critical current density, Jc and irreversible fields Birr of MgB2 are significantly improved. For the best sample, at 20K, 4T and 10K, 6T, the Jc reach 2400 and 3700 A cm-2, which is higher than normal porous sample by a factor of 20 and 8, respectively; and the Birr at 20 K reaches 5.10 T.

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EFFECT OF NANO-Y-ZrO2 ADDITION ON THE MICROSTRUCTURE AND CRITICAL CURRENT DENSITY OF MgB2 SUPERCONDUCTORS

International Journal of Nanoscience ◽

10.1142/s0219581x04002383 ◽

2004 ◽

Vol 03 (04n05) ◽

pp. 563-569 ◽

Cited By ~ 1

Author(s):

Q. W. YAO ◽

X. L. WANG ◽

A. H. LI ◽

S. X. DOU ◽

P. R. MUNROE

Keyword(s):

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Magnetic Measurements ◽

Transmission Electron ◽

Long Time ◽

Powder Addition ◽

Short Time ◽

Mgb2 Superconductors

Polycrystalline MgB 2 samples with 0, 5, 10, and 20 wt% nano- Y - ZrO 2 (YSZ) powder addition were prepared by short time, as little as several minutes, or long time in-situ reaction process. The phases, microstructures and flux pinning behaviors were characterized using X-ray diffractometry (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscope (TEM) and Magnetic Measurements. Results indicated that nano-YSZ particles included in MgB 2 grains. Samples doped with 10wt% YSZ powders showed new record of critical current density Jc as high as 1×106 and 4×106 A/cm 2 in low magnetic fields at 30 and 20K, respectively. However, the Jc drops faster compared to that made by long time sintering samples. It is proposed that the improved Jc in low fields was due to the enhanced density of the sample, which was caused by the YSZ nano-particle inclusion.

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