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- Australian Institute for Innovative Materials - Papers (12)
- Shi Xue Dou (10)
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- Jianli Wang (2)
- Josip Horvat (2)
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- Guna S. Selvaduray (1)
- Sarma Mulukutla (1)
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Articles 1 - 30 of 49
Full-Text Articles in Engineering
Type-B Energetic Processes: Their Identification And Implications, James Weifu Lee
Type-B Energetic Processes: Their Identification And Implications, James Weifu Lee
Chemistry & Biochemistry Faculty Publications
We have now identified two thermodynamically distinct types (A and B) of energetic processes naturally occurring on Earth. Type-A energy processes, such as classical heat engines, apparently well follow the second law of thermodynamics; Type-B energy processes, such as the newly discovered thermotrophic function that isothermally utilizes environmental heat energy to perform useful work in driving ATP synthesis, follow the first law of thermodynamics (conservation of mass and energy) but do not have to be constrained by the second law, owing to their special asymmetric functions. Several Type-B energy processes such as asymmetric function-gated isothermal electricity production and epicatalysis have …
Development Of High Kinetic Inductance Superconducting Nanowire Devices On High Permittivity Strontium Titanate Substrates, Jamie Timmons
Development Of High Kinetic Inductance Superconducting Nanowire Devices On High Permittivity Strontium Titanate Substrates, Jamie Timmons
UNF Graduate Theses and Dissertations
This thesis involves the fabrication and characterization of devices made from two different superconducting materials: yttrium barium copper oxide (YBCO), a high-TC complex oxide, and niobium nitride (NbN), a low-TC transition metal nitride. Both types of devices are fabricated on strontium titanate substrates, which provides a good lattice match to YBCO and also an extremely large permittivity at low temperature. We demonstrate that wet etching of YBCO thin films via bromine can be a viable microfrabriation technique for the material. Using approximately 35 nm thick epitaxially grown YBCO on an STO substrate, we were able to fabricate YBCO “microwires” with …
Superheating Field In Superconductors With Nanostructured Surfaces, W. P. M. R. Pathirana, A. Gurevich
Superheating Field In Superconductors With Nanostructured Surfaces, W. P. M. R. Pathirana, A. Gurevich
Physics Faculty Publications
We report calculations of a dc superheating field Hsh in superconductors with nanostructured surfaces. Numerical simulations of the Ginzburg-Landau (GL) equations were performed for a superconductor with an inhomogeneous impurity concentration, a thin superconducting layer on top of another superconductor, and superconductor-insulator-superconductor (S-I-S) multilayers.The superheating field was calculated taking into account the instability of the Meissner state with a nonzero wavelength along the surface, which is essential for realistic values of the GL parameter κ. Simulations were done for the materials parameters of Nb and Nb3Sn at different values of κ and the mean free paths. We …
Electrical And Magnetic Properties Of High Temperature Superconductors Using Varying Forms Of Data Acquisition, Aryn M. Hays, Lindsay Bechtel, Colton Turbeville, Anthony Johnsen, Chris A. Tanner
Electrical And Magnetic Properties Of High Temperature Superconductors Using Varying Forms Of Data Acquisition, Aryn M. Hays, Lindsay Bechtel, Colton Turbeville, Anthony Johnsen, Chris A. Tanner
The Journal of Advanced Undergraduate Physics Laboratory Investigations, JAUPLI-B
High temperature superconductors (HTS) are materials that display superconducting properties at temperatures above that of liquid nitrogen. Possible applications and ease of use in a typical physics laboratory make them interesting systems to study. In this experiment we measured the critical temperatures of two samples made of different HTS materials. We also devised a method that makes taking data automated.
Magnetic Field Sensors For Detection Of Trapped Flux In Superconducting Radio Frequency Cavities, Ishwari Prasad Parajuli, Gianluigi Ciovati, Jean R. Delayen
Magnetic Field Sensors For Detection Of Trapped Flux In Superconducting Radio Frequency Cavities, Ishwari Prasad Parajuli, Gianluigi Ciovati, Jean R. Delayen
Physics Faculty Publications
Superconducting radio frequency (SRF) cavities are fundamental building blocks of modern particle accelerators. They operate at liquid helium temperatures (2–4 K) to achieve very high quality factors (1010–1011). Trapping of magnetic flux within the superconductor is a significant contribution to the residual RF losses, which limit the achievable quality factor. Suitable diagnostic tools are in high demand to understand the mechanisms of flux trapping in technical superconductors, and the fundamental components of such diagnostic tools are magnetic field sensors. We have studied the performance of commercially available Hall probes, anisotropic magnetoresistive sensors, and flux-gate magnetometers with …
Superconductivity In La₂Ni₂In, Jannis Maiwald, Igor I. Mazin, Alex Gurevich, Meigan Aronson
Superconductivity In La₂Ni₂In, Jannis Maiwald, Igor I. Mazin, Alex Gurevich, Meigan Aronson
Physics Faculty Publications
We report here the properties of single crystals of La2Ni2In. Electrical resistivity and specific heat measurements concur with the results of density functional theory calculations, finding that La2Ni2In is a weakly correlated metal, where the Ni magnetism is almost completely quenched, leaving only a weak Stoner enhancement of the density of states. Superconductivity is observed at temperatures below 0.9 K. A detailed analysis of the field and temperature dependencies of the resistivity, magnetic susceptibility, and specific heat at the lowest temperatures reveals that La2Ni2In is a dirty type-II …
Effect Of Layer Thickness On Structural, Morphological And Superconducting Properties Of Nb3Sn Films Fabricated By Multilayer Sequential Sputtering, M. N. Sayeed, U. Pudasaini, C. E. Reece, G. V. Eremeev, H. E. Elsayed-Ali
Effect Of Layer Thickness On Structural, Morphological And Superconducting Properties Of Nb3Sn Films Fabricated By Multilayer Sequential Sputtering, M. N. Sayeed, U. Pudasaini, C. E. Reece, G. V. Eremeev, H. E. Elsayed-Ali
Electrical & Computer Engineering Faculty Publications
Superconducting Nb3Sn films can be synthesized by controlling the atomic concentration of Sn. Multilayer sequential sputtering of Nb and Sn thin films followed by high temperature annealing is considered as a method to fabricate Nb3Sn films, where the Sn composition of the deposited films can be controlled by the thickness of alternating Nb and Sn layers. We report on the structural, morphological and superconducting properties of Nb3Sn films fabricated by multilayer sequential sputtering of Nb and Sn films on sapphire substrates followed by annealing at 950 °C for 3 h. We have investigated the …
Direct Synthesis Of Graphene On Niobium And Niobium Nitride, Robin Ekeya, Otto Zietz
Direct Synthesis Of Graphene On Niobium And Niobium Nitride, Robin Ekeya, Otto Zietz
Undergraduate Research & Mentoring Program
Since its isolation by mechanical exfoliation in 2004, graphene has attracted enormous interest from the scientific community not the least because of its unique physical and electronic properties. Among these, graphene’s ballistic electron transport and proximity induced superconductivity make graphene-superconductor (GS) hybrid structures a scientifically promising area.
Vibration Effect On Magnetization And Critical Current Density Of Superconductors, Igor A. Golovchanskiy, Alexey V. Pan, Jonathan George, Frederick Wells, Sergey Fedoseev, Anatoly B. Rosenfeld
Vibration Effect On Magnetization And Critical Current Density Of Superconductors, Igor A. Golovchanskiy, Alexey V. Pan, Jonathan George, Frederick Wells, Sergey Fedoseev, Anatoly B. Rosenfeld
Australian Institute for Innovative Materials - Papers
In this work the effect of vibrations on critical current density ( Jc) of superconductors has been studied. The vibrations are shown to affect Jc of all types of superconductors during their measurements, employing a vibrating sample magnetometer (VSM). Increasing vibration frequency ( f ) and/or amplitude (A) leads to progressive reduction of Jc as a function of magnetic field (Ba). The effect of vibrations is substantially stronger in thin films. It leads to development of unexpected kinks on Jc (Ba) curves. Analysis of magnetization loops and relaxation of magnetization in YBCO films revealed that the vibration effect can be …
Improvement In Structure And Superconductivity Of Bulk Fese0.5te0.5 Superconductors By Optimizing Sintering Temperature, Ning Chen, Yongchang Liu, Zongqing Ma, Liming Yu, Huijun Li
Improvement In Structure And Superconductivity Of Bulk Fese0.5te0.5 Superconductors By Optimizing Sintering Temperature, Ning Chen, Yongchang Liu, Zongqing Ma, Liming Yu, Huijun Li
Australian Institute for Innovative Materials - Papers
Sintering temperature plays a vital role in the evolution of phase structure and microstructure in polycrystalline FeSe0.5Te0.5 bulks fabricated by the two-step sintering method, and thus significantly influences their superconducting properties. Elevated sintering temperature (600-700°C) at second step facilitates the substitution of Te into the superconducting phase, which leads to the increased lattice distortion and thus contributes to the enhancement of superconductivity (the value of Tc reaches 15.6K). At the same time, the accelerated growth of the superconducting grains and the improved homogeneity motivated by elevated sintering temperature serve as the main reason for the sharp superconducting transition.
Hydrostatic Pressure: A Very Effective Approach To Significantly Enhance Critical Current Density In Granular Iron Pnictide Superconductors, Babar Shabbir, Xiaolin Wang, Shaban Reza Ghorbani, C Shekhar, S X. Dou, O.N Srivastava
Hydrostatic Pressure: A Very Effective Approach To Significantly Enhance Critical Current Density In Granular Iron Pnictide Superconductors, Babar Shabbir, Xiaolin Wang, Shaban Reza Ghorbani, C Shekhar, S X. Dou, O.N Srivastava
Australian Institute for Innovative Materials - Papers
Pressure is well known to significantly raise the superconducting transition temperature, Tc, in both iron pnictides and cuprate based superconductors. Little work has been done, however, on how pressure can affect the flux pinning and critical current density in the Fe-based superconductors. Here, we propose to use hydrostatic pressure to significantly enhance flux pinning and Tc in polycrystalline pnictide bulks. We have chosen Sr4V2O6Fe2As2 polycrystalline samples as a case study. We demonstrate that the hydrostatic pressure up to 1.2 GPa can not only significantly increase Tc from …
Controllable Morphology Of Flux Avalanches In Microstructured Superconductors, M Motta, F Colauto, J I. Vestgarden, Joachim Fritzsche, M Timmermans, J Cuppens, C Attanasio, C Cirillo, V V. Moshchalkov, J Van De Vondel, Tom H. Johansen, W A. Ortiz, A V. Silhanek
Controllable Morphology Of Flux Avalanches In Microstructured Superconductors, M Motta, F Colauto, J I. Vestgarden, Joachim Fritzsche, M Timmermans, J Cuppens, C Attanasio, C Cirillo, V V. Moshchalkov, J Van De Vondel, Tom H. Johansen, W A. Ortiz, A V. Silhanek
Australian Institute for Innovative Materials - Papers
The morphology of abrupt bursts of magnetic flux into superconducting films with engineered periodic pinning centers (antidots) has been investigated. Guided flux avalanches of thermomagnetic origin develop a treelike structure, with the main trunk perpendicular to the borders of the sample, while secondary branches follow well-defined directions determined by the geometrical details of the underlying periodic pinning landscape. Strikingly, we demonstrate that in a superconductor with relatively weak random pinning the morphology of such flux avalanches can be fully controlled by proper combinations of lattice symmetry and antidot geometry. Moreover, the resulting flux patterns can be reproduced, to the finest …
Magnetic Field Processing To Enhance Critical Current Densities Of Mgb2 Superconductors, S X. Dou, Wai Kong Yeoh, Olga V. Shcherbakova, Josip Horvat, Jung Ho Kim, Alexey V. Pan, David Wexler, Yongqing Li, W X. Li, Z M. Ren, Paul G. Munroe, J Z. Cui
Magnetic Field Processing To Enhance Critical Current Densities Of Mgb2 Superconductors, S X. Dou, Wai Kong Yeoh, Olga V. Shcherbakova, Josip Horvat, Jung Ho Kim, Alexey V. Pan, David Wexler, Yongqing Li, W X. Li, Z M. Ren, Paul G. Munroe, J Z. Cui
Josip Horvat
A magnetic field of up to 12T was applied during the sintering process of pure MgB2 and carbon nanotube(CNT)dopedMgB2wires. The authors have demonstrated that magnetic field processing results in grain refinement, homogeneity, and enhancement in Jc(H) and Hirr. The extent of improvement in Jc increases with increasing field. The Jc for a 10T field processed CNTdoped sample increases by a factor of 3 at 10K and 8T and at 20K and 5T, respectively. Hirr for the 10T field processed CNTdoped sample reached 9T at 20K, which exceeded the best value of SiC dopedMgB2 at 20K. Magnetic field processing reduces the …
Flux Dynamics In (Y, Nd)1ba2cu3o7 Superconductors, A S Mahmoud, Josip Horvat, S X. Dou
Flux Dynamics In (Y, Nd)1ba2cu3o7 Superconductors, A S Mahmoud, Josip Horvat, S X. Dou
Josip Horvat
The vortex dynamics of (Y, Nd)Ba2Cu3O7−δ ((Y, Nd)123) superconductors have been studied using magnetic relaxation measurements obtained at different sweep rates. The temperature dependence of the dynamic relaxation rate (Q) is found to be not vanishing at T = 0 K, and also showed well developed maxima becoming broader and tending to move to higher temperatures with decreasing magnetic field. At temperatures close to the critical temperature (T c ), Q(T) showed well-developed minima becoming deeper and tending to move to lower temperatures with increasing field. These minima appeared to occur approximately at the same reduced temperature position [ T/T …
Sugar As An Optimal Carbon Source For The Enhanced Performance Of Mgb2 Superconductors At High Magnetic Fields, Olga Shcherbakova, Alexey Pan, Jianli Wang, Andrey Shcherbakov, S. Dou, David Wexler, E Babic, M Jercinovic, O Husnjak
Sugar As An Optimal Carbon Source For The Enhanced Performance Of Mgb2 Superconductors At High Magnetic Fields, Olga Shcherbakova, Alexey Pan, Jianli Wang, Andrey Shcherbakov, S. Dou, David Wexler, E Babic, M Jercinovic, O Husnjak
Jianli Wang
In this paper we report the results of an extended study of the effect of sugar doping on the structural and electromagnetic properties of MgB2 superconductors. High values of the upper critical field (Bc2) of 36 T and the irreversibility field (Birr) of 27 T have been estimated at the temperature of 5 K in a bulk MgB2 sample with the addition of 10 wt% of sugar. The critical current density (Jc(Ba)) of sugar-doped samples has been significantly improved in the high field region. The value of transport Jc has reached as high as 108 A m-2 at 10 T …
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga Shcherbakova, Alexey Pan, Jianli Wang, Andrey Shcherbakov, S. Dou, David Wexler
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga Shcherbakova, Alexey Pan, Jianli Wang, Andrey Shcherbakov, S. Dou, David Wexler
Jianli Wang
Structural analysis and electromagnetic measurements have been performed on a range of samples prepared by the liquid mixing approach to doping MgB2 are sugar, malic acid, and polycarbosilane. The results obtained have allowed us to clarify the contributions of the factors limiting critical current at low magnetic fields in doped MgB2.
Nanocoating Of Particles For Optimal Doping And Universal Enhancement Of Current-Carrying Ability In "Organic" Mgb2-Xcx Superconductors, Olga V. Shcherbakova, Alexey V. Pan, S X. Dou, Rashmi Nigam, David Wexler
Nanocoating Of Particles For Optimal Doping And Universal Enhancement Of Current-Carrying Ability In "Organic" Mgb2-Xcx Superconductors, Olga V. Shcherbakova, Alexey V. Pan, S X. Dou, Rashmi Nigam, David Wexler
Shi Xue Dou
The universal approach of liquid mixing has been found to produce “organic” MgB2−xCx superconductors with structural and supercurrent-carrying properties unattainable by other techniques. We show by transmission electron microscopy combined with energy dispersive spectroscopy that these unique properties are enabled through coating of boron particles with a nanolayer of carbon. The subsequent reaction between carbon-encapsulated boron and magnesium results in enhanced carbon content x in the crystal lattice, as determined by x-ray diffraction pattern analysis. Among various carbon-containing compounds investigated, polycarbosilane has been found to be the optimal dopant for MgB2 superconductor, producing the largest critical current density due to …
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga V. Shcherbakova, Alexey V. Pan, Jianli Wang, Andrey Shcherbakov, S. X. Dou, David Wexler
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga V. Shcherbakova, Alexey V. Pan, Jianli Wang, Andrey Shcherbakov, S. X. Dou, David Wexler
Shi Xue Dou
Structural analysis and electromagnetic measurements have been performed on a range of samples prepared by the liquid mixing approach to doping MgB2 are sugar, malic acid, and polycarbosilane. The results obtained have allowed us to clarify the contributions of the factors limiting critical current at low magnetic fields in doped MgB2.
Comparison Of Small-Field Behaviour In Mgb2, Low And High Temperature Superconductors, Alexey V. Pan, S X. Dou
Comparison Of Small-Field Behaviour In Mgb2, Low And High Temperature Superconductors, Alexey V. Pan, S X. Dou
Shi Xue Dou
Different types of superconductors have been investigated at small magnetic fields (Ba) over wide temperature (T) ranges at different Ba orientations. It has been shown that the temperature dependence of the characteristic field (B*), separating the Ba-independent critical current density (Jc) plateau (single vortex pinning regime) and the region with Jc(Ba) (collective pinning), can be attributed either to the temperature dependence of the magnetic penetration depth for Nb-film and MgB2bulk superconductors, or to thermally activated processes for Bi-based superconductors and YBa2Cu3O7−δ superconducting films. In both cases the vortex pinning influence appears to have a secondary role, affecting the effective vortex …
Peak Effect In The Critical Current Of Type Ii Superconductors With Strong Magnetic Vortex Pinning, X B. Xu, H Fangohr, X N. Xu, M Gu, Z H Wang, S M. Ji, Shichao Ding, Dongqi Shi, S. X. Dou
Peak Effect In The Critical Current Of Type Ii Superconductors With Strong Magnetic Vortex Pinning, X B. Xu, H Fangohr, X N. Xu, M Gu, Z H Wang, S M. Ji, Shichao Ding, Dongqi Shi, S. X. Dou
Shi Xue Dou
We perform 2D Langevin simulations studying the peak effect (PE) of the critical current taking into account the temperature dependence of the competing forces. We observe and report that the PE results from the competition of vortex-vortex interactions and vortex-pin interactions which have different temperature dependencies. The simulations reveal that the PE can take place only for certain pinning strengths, densities of pinning centres, and driving forces, which is in good agreement with experiments. No apparent vortex order-disorder transition is observed across the PE regime. In addition, the PE is a dynamical phenomenon, and thermal fluctuations can speed up the …
Benzoic Acid Doping To Enhance Electromagnetic Properties Of Mgb2 Superconductors, W. X. Li, Y. Li, M. Y. Zhu, R. H. Chen, X. Xu, W. K. Yeoh, J. H. Kim, S. X. Dou
Benzoic Acid Doping To Enhance Electromagnetic Properties Of Mgb2 Superconductors, W. X. Li, Y. Li, M. Y. Zhu, R. H. Chen, X. Xu, W. K. Yeoh, J. H. Kim, S. X. Dou
Shi Xue Dou
The effect of benzoic acid doping on lattice parameters, microstructure, critical temperature (T-c), critical current density (J(c)) and flux pinning force of MgB2 has been studied. In this work we used benzoic acid as an example of aromatic acids as an additive to MgB2. For different sintering process, actual carbon (C) substitution for boron (B) was estimated to be from 3.5 at% to 5.0 at% of B while T-c dropped about 2-4 K. The advantages of aromatic acid doping include homogeneous mixing of precursor powders, avoidance of expansive nano-additives, production of highly reactive C and significant enhancement in J(c) of …
Flux Dynamics In (Y, Nd)1ba2cu3o7 Superconductors, A S Mahmoud, Josip Horvat, S X. Dou
Flux Dynamics In (Y, Nd)1ba2cu3o7 Superconductors, A S Mahmoud, Josip Horvat, S X. Dou
Shi Xue Dou
The vortex dynamics of (Y, Nd)Ba2Cu3O7−δ ((Y, Nd)123) superconductors have been studied using magnetic relaxation measurements obtained at different sweep rates. The temperature dependence of the dynamic relaxation rate (Q) is found to be not vanishing at T = 0 K, and also showed well developed maxima becoming broader and tending to move to higher temperatures with decreasing magnetic field. At temperatures close to the critical temperature (T c ), Q(T) showed well-developed minima becoming deeper and tending to move to lower temperatures with increasing field. These minima appeared to occur approximately at the same reduced temperature position [ T/T …
Vortex Dynamics For Low- Type-Ii Superconductors, X B Xu, H Fangohr, Z H Wang, M Gu, S.L. Liu, Dongqi Shi, S. X. Dou
Vortex Dynamics For Low- Type-Ii Superconductors, X B Xu, H Fangohr, Z H Wang, M Gu, S.L. Liu, Dongqi Shi, S. X. Dou
Shi Xue Dou
Based on a model appropriate for “marginally type-II” superconducting system, we study the dynamics of vortices with competing interactions by Langevin dynamics simulation. In addition to pinned states and plastic flow, we find that the moving vortex system forms ordered bubble configurations and stripe structures, depending on pinning strength and driving force. The vortex system exhibits a marked hysteresis in its velocity-force characteristic, which results from a dynamical stripe reordering due to intervortex attraction.
Magnetic Field Processing To Enhance Critical Current Densities Of Mgb2 Superconductors, S X. Dou, Wai Kong Yeoh, Olga V. Shcherbakova, Josip Horvat, Jung Ho Kim, Alexey V. Pan, David Wexler, Yongqing Li, W X. Li, Z M. Ren, Paul G. Munroe, J Z. Cui
Magnetic Field Processing To Enhance Critical Current Densities Of Mgb2 Superconductors, S X. Dou, Wai Kong Yeoh, Olga V. Shcherbakova, Josip Horvat, Jung Ho Kim, Alexey V. Pan, David Wexler, Yongqing Li, W X. Li, Z M. Ren, Paul G. Munroe, J Z. Cui
Shi Xue Dou
A magnetic field of up to 12T was applied during the sintering process of pure MgB2 and carbon nanotube(CNT)dopedMgB2wires. The authors have demonstrated that magnetic field processing results in grain refinement, homogeneity, and enhancement in Jc(H) and Hirr. The extent of improvement in Jc increases with increasing field. The Jc for a 10T field processed CNTdoped sample increases by a factor of 3 at 10K and 8T and at 20K and 5T, respectively. Hirr for the 10T field processed CNTdoped sample reached 9T at 20K, which exceeded the best value of SiC dopedMgB2 at 20K. Magnetic field processing reduces the …
Carbohydrate Doping To Enhance Electromagnetic Properties Of Mgb2 Superconductors, Jung Ho Kim, Sihai Zhou, Md S. Hossain, Alexey V. Pan, S X. Dou
Carbohydrate Doping To Enhance Electromagnetic Properties Of Mgb2 Superconductors, Jung Ho Kim, Sihai Zhou, Md S. Hossain, Alexey V. Pan, S X. Dou
Shi Xue Dou
The effect of carbohydrate doping on lattice parameters, microstructure, Tc, Jc, Hirr, and Hc2 of MgB2 has been studied. In this work the authors used malic acid as an example of carbohydrates as an additive to MgB2. The advantages of carbohydrate doping include homogeneous mixing of precursor powders, avoidance of expansive nanoadditives, production of highly reactive C, and significant enhancement in Jc, Hirr, and Hc2 of MgB2, compared to undoped samples. The Jc for MgB2+30 wt% C4H6O5 sample was increased by a factor of 21 at 5 K and 8 T without degradation of self-field Jc.
Fluctuation Of Mean Free Path And Transition Temperature Induced Vortex Pinning In (Ba,K)Fe2as2 Superconductors, S R. Ghorbani, Xiaolin Wang, Mahboobeh Shahbazi, S. X. Dou, C T. Lin
Fluctuation Of Mean Free Path And Transition Temperature Induced Vortex Pinning In (Ba,K)Fe2as2 Superconductors, S R. Ghorbani, Xiaolin Wang, Mahboobeh Shahbazi, S. X. Dou, C T. Lin
Shi Xue Dou
The vortex pinning mechanisms of Ba0.72K0.28Fe2As2 single crystal have been studied systematically as a function of temperature and magnetic field. The temperature dependence of the critical current density, Jc(T), was analysed within the collective pinning model at different magnetic fields. It was found that both the dl pinning mechanism, i.e., pinning associated with charge-carrier mean free path fluctuation, and the dTc pinning mechanism, which is associated with spatial fluctuations of the transition temperature, coexist in the Ba0.72K0.28Fe2As2 single crystal in fields smaller than 4 T. Their contributions are strongly temperature and magnetic field dependent. At lower temperature and B
Superconducting Windings In A Power Transformer, An Old Question With A New Answer, James M. Feldman, Bell A. Cogbill, M. S. Sarma
Superconducting Windings In A Power Transformer, An Old Question With A New Answer, James M. Feldman, Bell A. Cogbill, M. S. Sarma
Sarma Mulukutla
This is the second of two papers examining the practicality of superconducting windings for large power transformers. The issues examined in this paper include elements of the behavior of superconducting tapes that would be important in power transformers, the refrigeration requirements for a step-up transformer of practical size, a coil structure appropriate to a superconducting winding and its cryogenic environment, current crowding in the end turns, and an estimate of the energy savings that a practical superconducting transformer could be expected to realize.
A Significant Improvement In Both Low- And High-Field Performance Of Mgb2 Superconductors Through Graphene Oxide Doping, K S B De Silva, S H Aboutalebi, Xun Xu, Xiaolin Wang, W X Li, Konstantin Konstantinov, S X. Dou
A Significant Improvement In Both Low- And High-Field Performance Of Mgb2 Superconductors Through Graphene Oxide Doping, K S B De Silva, S H Aboutalebi, Xun Xu, Xiaolin Wang, W X Li, Konstantin Konstantinov, S X. Dou
Australian Institute for Innovative Materials - Papers
The effects of graphene oxide (GO) doping on the superconducting properties of MgB2 were studied using bulk samples made by the diffusion method. Homogeneous dispersions of GO in tetrahydrofuran were obtained through a novel synthesis method, which is then chemically doped with MgB2. It was found that GO doping significantly improves the critical current density, under both low and high magnetic fields, which distinguishes GO from all the other elements doped into MgB2 so far. 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Opportunities In Power Applications Of Superconductors, C Sloggett, Christopher Cook, S Dou, N Savvides, A. Secrett
Opportunities In Power Applications Of Superconductors, C Sloggett, Christopher Cook, S Dou, N Savvides, A. Secrett
Christopher Cook
Since the discovery of high temperature superconductors in 1986/87, rapid progress has been made in the development of these materials in forms suitable for engineering applications. Amongst the most important are flexible silver/superconductor composite wires or tapes capable of carrying tens of amperes at liquid nitrogen temperatures essentially without loss. Diverse applications in areas such as electricity supply, medicine industry and transportation now seem accessible and a total market in excess of US $l5O billion is forecast for the year 2020. A consortium consisting of Metal Manufactures Ltd. (MM), the University of Wollongong and CSIRO has produced high quality tapes …
Fluctuation Of Mean Free Path And Transition Temperature Induced Vortex Pinning In (Ba,K)Fe2as2 Superconductors, S R. Ghorbani, Xiaolin Wang, Mahboobeh Shahbazi, S. X. Dou, C T. Lin
Fluctuation Of Mean Free Path And Transition Temperature Induced Vortex Pinning In (Ba,K)Fe2as2 Superconductors, S R. Ghorbani, Xiaolin Wang, Mahboobeh Shahbazi, S. X. Dou, C T. Lin
Faculty of Engineering - Papers (Archive)
The vortex pinning mechanisms of Ba0.72K0.28Fe2As2 single crystal have been studied systematically as a function of temperature and magnetic field. The temperature dependence of the critical current density, Jc(T), was analysed within the collective pinning model at different magnetic fields. It was found that both the dl pinning mechanism, i.e., pinning associated with charge-carrier mean free path fluctuation, and the dTc pinning mechanism, which is associated with spatial fluctuations of the transition temperature, coexist in the Ba0.72K0.28Fe2As2 single crystal in fields smaller than 4 T. Their contributions are strongly temperature and magnetic field dependent. At lower temperature and B