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The effect of doping MgB2 with carbon nanotubes on transition temperature, lattice parameters, critical current density and flux pinning was studied for MgB2-xCx with x = 0, 0.05, 0.1, 0.2 and 0.3. The carbon substitution for B was found to…

Superconductivity · Physics 2007-05-23 S. X. Dou , W. K. Yeoh , J. Horvat , M. Ionescu

We investigated the doping effects of SWCNTs and MWCNTs on the Tc, lattice parameters, Jc(B), microstructure, and Hc2 of MgB2/Fe wire. These effects systematically showed the following sequence for Tc and the a-axis: the SWCNT doped wire <…

Superconductivity · Physics 2009-11-11 J. H. Kim , W. K. Yeoh , M. J. Qin , X. Xu , S. X. Dou , P. Munroe , H. Kumakura , T. Nakane , C. H. Jiang

The effect of nano-C doping on the microstructure and superconducting properties of Fe-sheathed MgB2 tapes prepared through the in-situ powder-in-tube method was studied. Heat treatment was performed at a low temperature of 650C for 1 h.…

Superconductivity · Physics 2015-06-25 Xianping Zhang , Yanwei Ma* , Aixia Xu , Yulei Jiao , Ling Xiao , S. Awaji , K. Watanabe , Huan Yang , Haihu Wen

In the present study, we report a systematic study of doping/ admixing of carbon nanotubes (CNTs) in different concentrations in MgB2. The composite material corresponding to MgB2+ x at.%CNTs (35 at.% > x > 0 at.%) have been prepared by…

Superconductivity · Physics 2007-05-23 Chandra Shekhar , Rajiv Giri , S. K. Malik* , O N Srivastava

A comparative study of pure, SiC, and C doped MgB2 wires has revealed that the SiC doping allowed C substitution and MgB2 formation to take place simultaneously at low temperatures. C substitution enhances Hc2, while the defects, small…

We investigated the effect of nanoscale-C doping on the critical current density Jc and irreversibility field Birr of Fe-sheathed MgB2 tapes prepared by the in-situ powder-in-tube method. The tapes were heat treated at 600-950C for 1 h.…

Superconductivity · Physics 2009-11-11 Yanwei Ma , Xianping Zhang , S. Awaji , Zhaoshun Gao , Dongliang Wang , Zhengguang Yu , G. Nishijima , K. Watanabe

Doping of MgB2 by nano-SiC and its potential for improvement of flux pinning was studied for MgB2-x(SiC)x/2 with x = 0, 0.2 and 0.3 and a 10wt% nano-SiC doped MgB2 samples. Co-substitution of B by Si and C counterbalanced the effects of…

Superconductivity · Physics 2009-11-07 S. X. Dou , S. Soltanian , J. Horvat , X. L. Wang , P. Munroe , S. H. Zhou , M. Ionescu , H. K. Liu , M. Tomsic

The rapid progress on MgB2 superconductor since its discovery[1] has made this material a strong competitor to low and high temperature superconductors (HTS) for applications with a great potential to catch the niche market such as in…

The use of MgB2 in superconducting applications still awaits for the development of a MgB2-based material where both current-carrying performance and critical magnetic field are optimized simultaneously. We achieved this by doping MgB2 with…

Superconductivity · Physics 2009-11-11 A. Serquis , G. Serrano , S. Moreno , ; L. Civale , B. Maiorov , ; F. Balakirev , M. Jaime

A review of current developments in the study of chemical doping effect on the superconducting properties of MgB2 wires and tapes is presented, based on the known literature data and our own results. The critical current density of MgB2 can…

Superconductivity · Physics 2015-05-14 Zhaoshun Gao , Yanwei Ma , Dongliang Wang , Xianping Zhang

Nanocarbon-doped Fe-sheathed MgB2 tapes with different doping levels were prepared by the in situ powder-in-tube method. Compared to the undoped tapes, Jc for all the C-doped samples was enhanced by more than an order of magnitude in…

Superconductivity · Physics 2009-11-11 Yanwei Ma , Xianping Zhang , G. Nishijima , K. Watanabe , Xuedong Bai

Polycrystalline MgB2-xCx samples with x=0.05, 0.1, 0.2, 0.3, 0.4 nano-particle carbon powder were prepared using an in-situ reaction method under well controlled conditions to limit the extent of C substitution. The phases, lattice…

Superconductivity · Physics 2015-06-24 S. Soltanian , J. Horvat , X. L. Wang , P. Munroe , S. X. Dou

We present ab initio calculations on the band structure and density of states of single wall semiconducting carbon nanotubes with high degrees (up to 25%) of B, Si and N substitution. The doping process consists of two phases: different…

Mesoscale and Nanoscale Physics · Physics 2015-01-13 E. Tetik

Employing strong electrostatic gating (liquid-ion gating), the position of the Fermi energy E_F (relative to the charge-neutrality point) was determined in multi-wall carbon nanotubes (MWNTs). E_F is negative (hole doping) and amounts to…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Christian Schönenberger , Mark Buitelaar , Michael Krüger , Isabelle Widmer , Thomas Nussbaumer , Mahdi Iqbal

With the relatively high critical temperature (Tc) of 39 K1 and the high critical current density (Jc) of > 100000 A/cm2 in moderate fields, magnesium diboride (MgB2) superconductors could offer the promise of important large-scale and…

Superconductivity · Physics 2007-05-23 J. H. Kim , S. Zhou , M. S. A. Hossain , A. V. Pan , S. X. Dou

Iron is an important sheath material for fabrication of MgB2 wires. However, the effect of Fe doping on the superconducting properties of MgB2 remains controversial. In this work, we present results of nano-scale Fe particle doping in to…

Superconductivity · Physics 2009-11-10 S. X. Dou , S. Soltanian , Y. Zhao , E. Getin , Z. Chen , J. Horvat

The critical temperature (TC) of MgB2, one of the key factors limiting its application, is highly desired to be improved. On the basis of the meta-material structure, we prepared a smart meta-superconductor structure consisting of MgB2…

Superconductivity · Physics 2017-12-04 Honggang Chen , Yongbo Li , Guowei Chen , Longxuan Xu , Xiaopeng Zhao

The effect of nanoscale-SiC doping of MgB2 was investigated using transport and magnetic measurements. It was found that there is a clear correlation between the critical temperature Tc, the resistivity r, the residual resistivity ratio,…

Superconductivity · Physics 2009-11-10 S. X. Dou , V. Braccini , S. Soltanian , R. Klie , Y. Zhu , S. Li , X. L. Wang , D. Larbalestier

The upper critical field, $H_{c2}$, of Mg(B$_{1-x}$C$_x$)$_2$ has been measured in order to probe the maximum magnetic field range for superconductivity that can be attained by C doping. Carbon doped boron filaments are prepared by CVD…

The nano-SiC doped MgB2/Fe wires were fabricated using a powder-in-tube method and an in-situ reaction process. The depression of Tc with increasing SiC doping level remained rather small due to the counterbalanced effect of Si and C…

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