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Physical Sciences and Mathematics

2008

MgB2

Articles 1 - 5 of 5

Full-Text Articles in Engineering

Reduction Of Superconducting Transition Temperature And Flux Pinning In Al And C Codoped Mgb2 With Insight From First-Principles Calculations, Aihua Li, Xiaolin Wang, S X. Dou, Qiwen Yao, Zhenxiang Cheng, Saeid Soltanian, J M. Yoo, P Munroe Jan 2008

Reduction Of Superconducting Transition Temperature And Flux Pinning In Al And C Codoped Mgb2 With Insight From First-Principles Calculations, Aihua Li, Xiaolin Wang, S X. Dou, Qiwen Yao, Zhenxiang Cheng, Saeid Soltanian, J M. Yoo, P Munroe

Australian Institute for Innovative Materials - Papers

We report for the first time the Al and C codoping effect on the structures and superconductivity in MgB2. It was found that both the lattice parameters and the Tc decreased monotonically with increasing doping level of both Al and C. The Tc dropped to 27.5 and 7 K for x=0.2 and for x =0.4, respectively. The reduction of Tc for the codoping was found to be quicker than for individual Al doping and slower than for individual C doping at the same doping levels. First-principles calculations indicated that the observed decrease in Tc …


Excess Mg Addition Mgb2 /Fe Wires With Enhanced Critical Current Density, Rong Zeng, Lin Lu, Wenxian Li, Jianli Wang, Dongqi Shi, Josip Horvat, S X. Dou, M Bhatia, M D Sumption, Edward W. Collings, Jaimoo Yoo, Mike Tomsic, M Rindfleisch Jan 2008

Excess Mg Addition Mgb2 /Fe Wires With Enhanced Critical Current Density, Rong Zeng, Lin Lu, Wenxian Li, Jianli Wang, Dongqi Shi, Josip Horvat, S X. Dou, M Bhatia, M D Sumption, Edward W. Collings, Jaimoo Yoo, Mike Tomsic, M Rindfleisch

Australian Institute for Innovative Materials - Papers

MgB2 /Fe wires with 10 at. % excess Mg produced by in situ powder-in-tube processing werecompared to normal stoichiometric MgB2 /Fe wires prepared by the same method. It was found thatthe critical current density Jc and the irreversibility field (Hirr) were significantly enhanced forMgB2 /Fe wires with excess Mg. The transport Jc for 10 at. % Mg excess samples sintered at 800 degrees C, measured at a field of up to 14 T, increased by a factor of 2 compared to that for the normal MgB2 wires. The best Jc results …


Flux-Pinning Mechanism In Silicone-Oil Doped Mgb2: Evidence For Charge-Carrier Mean Free Path Fluctuation Pinning, Shaban R. Ghorbani, Xiaolin Wang, S X. Dou, Sung-Ik Lee, Md S. Hossain Jan 2008

Flux-Pinning Mechanism In Silicone-Oil Doped Mgb2: Evidence For Charge-Carrier Mean Free Path Fluctuation Pinning, Shaban R. Ghorbani, Xiaolin Wang, S X. Dou, Sung-Ik Lee, Md S. Hossain

Australian Institute for Innovative Materials - Papers

Flux-pinning mechanism of MgB2 doped with 10 wt % silicone-oil sintered at low and high temperatures has been investigated by magnetic measurements. The field dependence of the critical current density, jc(B), was analysed within the collective pinning model. A crossover field, Bsb, from the single vortex to the small vortex bundle-pinning regime was observed. For both types of sintered samples, the temperature dependence of Bsb(T) at low temperature is in good agreement with the δl pinning mechanism, i.e., pinning associated with charge-carrier mean free path fluctuation. At temperatures close to the critical …


High Field Performance Of Nano-Diamond Doped Mgb2 Superconductor, Arpita Vajpayee, V P. Awana, H Kishan, Anant Narlikar, G L. Bhalla, Xiaolin Wang Jan 2008

High Field Performance Of Nano-Diamond Doped Mgb2 Superconductor, Arpita Vajpayee, V P. Awana, H Kishan, Anant Narlikar, G L. Bhalla, Xiaolin Wang

Australian Institute for Innovative Materials - Papers

The results from magnetotransport and magnetization of nanodiamond doped MgB2-nDx are reported. Superconducting transition temperature (Tc) is not affected significantly by x up to x =0.05 and latter decreases slightly for higher x>0.05. R(T) vs H measurements show higher Tc values under same applied magnetic fields for the nanodiamond added samples, resulting in higher estimated Hc2 values. From the magnetization measurements, it was found that irreversibility field value Hirr for the pristine sample is 7.5 T at 4 K and the same is increased to 13.5 T for 3 wt % …


Correlation Between Doping Induced Disorder And Superconducting Properties In Carbohydrate Doped Mgb2, Jung Ho Kim, S X. Dou, Sangjun Oh, M Jercinovic, E Babic, T Nakane, Hiroaki Kumakura Jan 2008

Correlation Between Doping Induced Disorder And Superconducting Properties In Carbohydrate Doped Mgb2, Jung Ho Kim, S X. Dou, Sangjun Oh, M Jercinovic, E Babic, T Nakane, Hiroaki Kumakura

Australian Institute for Innovative Materials - Papers

A comprehensive study of the effects of carbohydrate doping on the superconductivity of MgB2 has been conducted. In accordance with the dual reaction model, more carbon substitution is achieved at lower sintering temperature. As the sintering temperature is lowered, lattice disorder is increased. Disorder is an important factor determining the transition temperature for the samples studied in this work, as evidenced from the correlations among the lattice strain, the resistivity, and the transition temperature. It is further shown that the increased critical current density in the high field region can be understood by a recently-proposed percolation model [M. Eisterer …