Physical Review B, ( ISI ), Volume (81), No (22), Year (2010-7)

Title : ( Enhancement of the in-field Jc of MgB2 via SiCl4 doping )

Authors: Xiao-Lin Wang , S.X. Dou , M.S.A. Hossain , Z.X. Cheng , X.Z. Liao , Shaban Reza Ghorbani , Q. W. Yao , J. H. Kim , T. Silver ,

Citation: BibTeX | EndNote

Abstract

We present the following results: 1) We introduce a doping source for MgB2, liquid SiCl4, which is free of C, to significantly enhance the irreversibility field (Hirr) , the upper critical field (Hc2), and the critical current density (Jc ) with a little reduction in the critical temperature (Tc). 2) Although Si can not be incorporated into the crystal lattice, a significant reduction in the a-axis lattice parameter was found, to the same extent as for carbon doping. 3) Based on the first-principles calculation, it is found that it is reliable to estimate the C concentration just from the reduction in the a-lattice parameter for C-doped MgB2 polycrystalline samples that are prepared at high sintering temperatures, but not for those prepared at low sintering temperatures. Strain effects and magnesium deficiency might be reasons for the a-lattice reduction in non-C or some of the C-added MgB2 samples. 4) The SiCl4-doped MgB2 shows much higher Jc with superior field dependence above 20 K compared to undoped MgB2 and MgB2 doped with various carbon sources. 5) We introduce a parameter, RHH (Hc2 / Hirr), which can clearly reflect the degree of flux-pinning enhancement, providing us with guidance for further enhancing Jc . 6) It was found that spatial variation in the charge-carrier mean free path is responsible for the flux-pinning mechanism in the SiCl4 treated MgB2 with large in-field Jc.

Keywords

, MgB2; Liquid SiCl4; Critical current density;Flux, pinning mechanism
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@article{paperid:1031167,
author = {Xiao-Lin Wang and S.X. Dou and M.S.A. Hossain and Z.X. Cheng and X.Z. Liao and Ghorbani, Shaban Reza and Q. W. Yao and J. H. Kim and T. Silver},
title = {Enhancement of the in-field Jc of MgB2 via SiCl4 doping},
journal = {Physical Review B},
year = {2010},
volume = {81},
number = {22},
month = {July},
issn = {2469-9950},
keywords = {MgB2; Liquid SiCl4; Critical current density;Flux-pinning mechanism},
}

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%0 Journal Article
%T Enhancement of the in-field Jc of MgB2 via SiCl4 doping
%A Xiao-Lin Wang
%A S.X. Dou
%A M.S.A. Hossain
%A Z.X. Cheng
%A X.Z. Liao
%A Ghorbani, Shaban Reza
%A Q. W. Yao
%A J. H. Kim
%A T. Silver
%J Physical Review B
%@ 2469-9950
%D 2010

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