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Full-Text Articles in Engineering
A Significant Improvement In The Superconducting Properties Of Mgb2 By Co-Doping With Graphene And Nano-Sic, K S B De Silva, X Xu, Xiaolin Wang, D Wexler, D Attard, F Xiang, S. X. Dou
A Significant Improvement In The Superconducting Properties Of Mgb2 By Co-Doping With Graphene And Nano-Sic, K S B De Silva, X Xu, Xiaolin Wang, D Wexler, D Attard, F Xiang, S. X. Dou
Faculty of Engineering - Papers (Archive)
The effects of graphene (G) and nanosilicon carbide (SiC) co-doping on the superconducting properties of MgB2 were studied using bulk samples. SiC remains one of the best dopants which can significantly improve the high field performance, while graphene is emerging as a new dopant for MgB2, which can improve the zero field critical current density (Jc). The superconducting properties characterized by Jc, the intergrain connectivity, and the critical fields were significantly improved by the use of both SiC and graphene as dopants.
Experimental Realization Of Superconducting Quantum Interference Devices With Topological Insulator Junctions, M Veldhorst, C G. Molenaar, Xiaolin Wang, H Hilgenkamp, A Brinkman
Experimental Realization Of Superconducting Quantum Interference Devices With Topological Insulator Junctions, M Veldhorst, C G. Molenaar, Xiaolin Wang, H Hilgenkamp, A Brinkman
Faculty of Engineering - Papers (Archive)
We demonstrate topological insulator (Bi2Te3) dc SQUIDs, based on superconducting Nb leads coupled to nano-fabricated Nb-Bi2Te3-Nb Josephson junctions. The high reproducibility and controllability of the fabrication process allow the creation of dc SQUIDs with parameters that are in agreement with design values. Clear critical current modulation of both the junctions and the SQUID with applied magnetic fields have been observed. We show that the SQUIDs have a periodicity in the voltage-flux characteristic of U0 of relevance to the ongoing pursuit of realizing interferometers for the detection of Majorana fermions in superconductor—topological insulator structures.
Crossing Point Phenomena () In Specific Heat Curves Of Superconducting Ferromagnets, Anuj Kumar, R P. Tandon, Jianli Wang, Rong Zeng, V P. S Awana
Crossing Point Phenomena () In Specific Heat Curves Of Superconducting Ferromagnets, Anuj Kumar, R P. Tandon, Jianli Wang, Rong Zeng, V P. S Awana
Faculty of Engineering - Papers (Archive)
Crossing point phenomena are one of the interesting and still puzzling effects in strongly correlated electron systems. We have synthesized RuSr2Gd1.4Ce0.6Cu2O10-delta (GdRu-1222) magneto-superconductor through the standard solid state reaction route and measured its magnetic, transport, and thermal properties. We also synthesized RuSr2Eu1.4Ce0.6Cu2O10-delta (EuRu-1222) then measured its heat capacity in zero magnetic fields for reference. The studied compounds crystallized in the tetragonal structure with space group I4/mmm. To explore the crossing point phenomena, the specific heat [C-p (T)] was investigated in the temperature range 1.9-250 K, under magnetic field of up to 70 kOe. Unfortunately though no magnetic and superconducting transitions …
Superconducting Properties Of Graphene Doped Magnesium Diboride, Xun Xu, Wenxian Li, Xiaolin Wang, S. X. Dou
Superconducting Properties Of Graphene Doped Magnesium Diboride, Xun Xu, Wenxian Li, Xiaolin Wang, S. X. Dou
Faculty of Engineering - Papers (Archive)
Graphene, carbon in the form of monolayer sheets, has revealed astonishing and unique chemical and physical properties, which have made it an extremely active research topic in both materials science and physics (Novoselov, K. S. et al., 2004). Through chemical and materials integration, graphene is being actively exploited in a range of technological applications (Stankovich, S. et al., 2006). Superconductors can carry electrical current without any energy dissipation. The combination of both graphene and a superconductor into a composite has great potential for electrical devices and large scale applications. MgB2, a superconductor with a simple composition and two-gap feature has …
Self-Doping Effect And Successive Magnetic Transitions In Superconducting Sr2 Vfeaso3, Guanghan Cao, Zhifeng Ma, Cao Wang, Yunlei Sun, Jinke Bao, Shuai Jiang, Yi Luo, Chunmu Feng, Yi Zhou, Zhi Xie, Fengchun Hu, Shiqiang Wei, I Nowik, I Felner, Lei Zhang, Zhu-An Xu, Fu-Chun Zhang
Self-Doping Effect And Successive Magnetic Transitions In Superconducting Sr2 Vfeaso3, Guanghan Cao, Zhifeng Ma, Cao Wang, Yunlei Sun, Jinke Bao, Shuai Jiang, Yi Luo, Chunmu Feng, Yi Zhou, Zhi Xie, Fengchun Hu, Shiqiang Wei, I Nowik, I Felner, Lei Zhang, Zhu-An Xu, Fu-Chun Zhang
Faculty of Engineering - Papers (Archive)
We have studied a quinary Fe-based superconductor Sr2VFeAsO3 by the measurements of x-ray diffraction, x-ray absorption, Mössbauer spectrum, resistivity, magnetization, and specific heat. This apparently undoped oxyarsenide is shown to be self-doped via electron transfer from the V3+ ions. We observed successive magnetic transitions within the VO2 layers: an antiferromagnetic transition at 150 K followed by a weak ferromagnetic transition at 55 K. The spin orderings within the VO2 planes are discussed based on mixed valence of V3+ and V4+.
Structural And Superconducting Properties Of Lafeas1-Xsbxo1-Yfy, Cao Wang, Zhifeng Ma, Shuai Jiang, Yuke Li, Zhu-An Xu, Guanghan Cao
Structural And Superconducting Properties Of Lafeas1-Xsbxo1-Yfy, Cao Wang, Zhifeng Ma, Shuai Jiang, Yuke Li, Zhu-An Xu, Guanghan Cao
Faculty of Engineering - Papers (Archive)
We report the antimony (Sb) doping effect in a prototype system of iron-based superconductors LaFeAsO1−y F y (y=0, 0.1, 0.15). X-ray powder diffraction indicates that the lattice parameters increase with Sb content within the doping limit. Rietveld structural refinements show that, with the partial substitution of Sb for As, the thickness of the Fe2As2 layers increases significantly, whereas that of the La2O2 layers shrinks simultaneously. So a negative chemical pressure is indeed “applied” to the superconducting-active Fe2As2 layers, in contrast to the effect of positive chemical pressure …
Superconducting Transition Width Under Magnetic Field In Mgb2 Polycrystalline Samples, C.C Wang, R Zeng, Xun Xu, S. X. Dou
Superconducting Transition Width Under Magnetic Field In Mgb2 Polycrystalline Samples, C.C Wang, R Zeng, Xun Xu, S. X. Dou
Faculty of Engineering - Papers (Archive)
A systematic study on the superconducting transition width as a function of the applied magnetic field was performed in polycrystalline MgB2. A quantitative, yet universal relation between the two parameters was observed in all of the ceramics. It was found that the width decreases linearly with decreasing field in pure MgB2 samples. Whereas, samples with boron and/or Mg atoms partially replaced by other elements show this linear relation in the temperature range below 0.7–0.8 of the superconducting transition temperature (corresponding to a field of about 2 T), at temperatures higher than this range, an abnormal upturn in …
Extended Dislocation-Based Pinning Mechanism In Superconducting Yba2cu3o7 Films, Serhiy Pysarenko, Alexey V. Pan, S X. Dou, Rashmi Nigam
Extended Dislocation-Based Pinning Mechanism In Superconducting Yba2cu3o7 Films, Serhiy Pysarenko, Alexey V. Pan, S X. Dou, Rashmi Nigam
Faculty of Engineering - Papers (Archive)
To describe the critical current density (Jc) as the function of applied magnetic field (Ba) in high quality YBa2Cu3O7 (YBCO) superconducting films, the vortex pinning mechanism along the structural domain boundaries of the films is developed. The boundaries, assumed to have low misorientation angles, are quantitatively considered to consist of individual edge dislocations acting as pinning wells, rather than a continuous boundary. This extended model accurately describes the experimental Jc(Ba) over the wide field and temperature ranges. Marginal deviations of the model from the …
Anisotrophic Currents And Flux Jumps In High-Tc Superconducting Films With Self-Organized Arrays Of Planar Defects, V Yurchenko, A.J Qviller, P.B Mozhaeva, J.E Mozhaeva, J.B Hansen, C Jacobsen, I.M Kotelyanskii, Alexey V. Pan, T H. Johansen
Anisotrophic Currents And Flux Jumps In High-Tc Superconducting Films With Self-Organized Arrays Of Planar Defects, V Yurchenko, A.J Qviller, P.B Mozhaeva, J.E Mozhaeva, J.B Hansen, C Jacobsen, I.M Kotelyanskii, Alexey V. Pan, T H. Johansen
Faculty of Engineering - Papers (Archive)
Regular arrays of planar defects with a period of a few nanometers can be introduced in superconducting YBa2Cu3O7-δ (YBCO) thin films by depositing them on vicinal (also called miscut or tilted) substrates. This results in the anisotropy of critical currents flowing in the plane of the film. We present results of real-time magneto-optical imaging (MOI) of magnetic flux distribution and dynamics in a series of YBCO thin films deposited on NdGaO3 substrates with different miscut angles θ. MOI allows reconstructing the current flow profiles. From the angle formed between domains with different …
Superconducting Magnetic Energy Storage Systems For Power System Applications, Danny Soetanto, K.W.E Cheng
Superconducting Magnetic Energy Storage Systems For Power System Applications, Danny Soetanto, K.W.E Cheng
Faculty of Engineering - Papers (Archive)
Advancement in both superconducting technologies and power electronics led to High Temperature Superconducting Magnetic Energy Storage Systems (SMES) having some excellent performances for use in power systems, such as rapid response (millisecond), high power (multi-MW), high efficiency, and four- quadrant control. This paper provides a review on SMES applications to power systems.
Hybrid Fuel Cell And Energy Storage Systems Using Superconducting Coil Or Batteries For Clean Electricity Generation, Danny Soetanto, Kai Ding
Hybrid Fuel Cell And Energy Storage Systems Using Superconducting Coil Or Batteries For Clean Electricity Generation, Danny Soetanto, Kai Ding
Faculty of Engineering - Papers (Archive)
This paper described a novel design of a hybrid fuel cell and energy storage system using high temperature superconducting energy storage system (HT-SMES) or batteries to meet fast changing load. The power electronic switches in the converter of the energy storage system are controlled in such a way that the amplitude and waveform of the inverter output current from the fuel cell is tightly regulated to follow a sinusoidal reference waveform. In this way, the energy storage system is used to supply the fast changing part of the load and the fuel cell system continuously supplies a constant full load …
Development And Performance Analysis Of A Saturated Core High Temperature Superconducting Fault Current Limiter, Jeffrey W. Moscrop, Scott Hopkins
Development And Performance Analysis Of A Saturated Core High Temperature Superconducting Fault Current Limiter, Jeffrey W. Moscrop, Scott Hopkins
Faculty of Engineering - Papers (Archive)
Recent international activity in the field of high voltage Fault Current Limiters (FCLs) has intensified since the North American blackout of 2003. A number of national and international peak body groups in the USA, Europe and Japan have been established to assess the need for FCLs and the issues associated with their design, specification, operation, protection and integration into the electricity grids. This paper details the development of a prototype 3-phase saturated core High Temperature Superconducting (HTS) FCL in Australia. Through experimental analysis, the performance of this device is characterised in terms of DC saturation, steady state performance, and fault …
Design And Development Of A 3-Phase Saturated Core High Temperature Superconducting Fault Current Limiter, Jeffrey W. Moscrop, Frank Darmann
Design And Development Of A 3-Phase Saturated Core High Temperature Superconducting Fault Current Limiter, Jeffrey W. Moscrop, Frank Darmann
Faculty of Engineering - Papers (Archive)
The occurrence of fault currents and system sensitivity to fault currents are both increasing in modern power systems. Along with extensive damage to network hardware, considerable consumer losses (due to network unavailability) can result from fault current events. One device that is designed to reduce the impact of fault currents and increase network availability is the fault current limiter (FCL). This paper describes the design and development of a 3-phase saturated core high temperature superconducting (HTS) FCL. This particular type of FCL exhibits negligible power losses during the un-faulted state and also provides instantaneous reaction and recovery during fault events. …
Superconducting Properties Of Mgb2 Wire Using Ball Milled Low Purity Boron, Xun Xu, Jung Ho Kim, Yun Zhang, Yue Zhao, Matthew Rindfleisch, Michael Tomsic
Superconducting Properties Of Mgb2 Wire Using Ball Milled Low Purity Boron, Xun Xu, Jung Ho Kim, Yun Zhang, Yue Zhao, Matthew Rindfleisch, Michael Tomsic
Faculty of Engineering - Papers (Archive)
MgB2/Fe wire samples were prepared by using ball-milled 96% boron (B) powder with strong semi-crystalline phase. We observed samples that contained ball-milled 96% B in comparison with one made from as-supplied commercial 96% B, with the results showing a significant enhancement in the high field transport critical current density (Jct) due to small grain size and better reactivity. However, the inter-grain connectivity became worse, which could lead to poor Jct in low field and an increased level of disorder.
Spin Wave Scattering And Interface Magnetism In Superconducting-Ferromagnet-Superconducting Hybrid Structures, Gustavo A. Alvarez, Xiaolin Wang, T Puzzer, Germanas Peleckis, S. X. Dou
Spin Wave Scattering And Interface Magnetism In Superconducting-Ferromagnet-Superconducting Hybrid Structures, Gustavo A. Alvarez, Xiaolin Wang, T Puzzer, Germanas Peleckis, S. X. Dou
Faculty of Engineering - Papers (Archive)
In this work we report on interlayer spin-polarized transport studies carried out on YBa2Cu3O7-δ/La2/3Sr1/3MnO3/YBa2Cu3O7-δ thin film multilayers. Anisotropic YBa2Cu3O7-δ high-temperature superconductors (YBCO) and the manganite La2/3Sr1/3MnO3 (LSMO) are layered metallic systems where the c-axis interlayer current transport occurs via sequential tunneling of charge carriers. The temperature dependence of the resistance R(T) for different applied fields shows that these heterostructures are clearly influenced by both the insulator-to-metal …
Coexistence Of Ferromagnetism And Cluster Glass State In Superconducting Ferromagnet Rusr2eu1.5ce0.5cu2o10, Rashmi Nigam, Alexey V. Pan, S X. Dou
Coexistence Of Ferromagnetism And Cluster Glass State In Superconducting Ferromagnet Rusr2eu1.5ce0.5cu2o10, Rashmi Nigam, Alexey V. Pan, S X. Dou
Faculty of Engineering - Papers (Archive)
Systematic dc and ac magnetic susceptibility measurements performed on RuSr2Eu1.5Ce0.5Cu2O10−δ (Ru1222) demonstrate a paramagnetic to ferromagnetic transition around 95 K. The third harmonic of the ac susceptibility reveals that the system undergoes a spin glass transition below 75 K. The features of the zero-field cooled and field cooled dc magnetization curves of Ru1222 material resemble those of a cluster glass state, rather than those of a canonical spin glass state. The magnetization versus applied field loops do not saturate, even at very high applied fields, resulting in the short range …
Dendritic Flux Avalanches In Superconducting Films, V Yurchenko, Y M. Galperin, Tom H. Johansen
Dendritic Flux Avalanches In Superconducting Films, V Yurchenko, Y M. Galperin, Tom H. Johansen
Faculty of Engineering - Papers (Archive)
Thermomagnetic instability in general, and dendritic flux avalanches in particular, have attracted considerable attention of both scientists and engineers working on superconductor applications. Though being harmful for the performance of many superconducting devices, the avalanches provide a fruitful playground for experimental and theoretical studies of complex dynamics of the vortex matter. In this paper we report on the progress in understanding the mechanisms responsible for the development of the giant magnetic avalanches. We review recent results on magneto-optical imaging of the fingering instability in superconducting films and analyze them on the basis of recent theoretical model that establishes criteria for …
Narrow Superconducting Window In Lafe1-Xnix Aso, Guanghan Cao, Shuai Jiang, Xiao Lin, Cao Wang, Yuke Li, Zhi Ren, Qian Tao, Chunmu Feng, Jianhui Dai, Zhu-An Xu, Fu-Chun Zhang
Narrow Superconducting Window In Lafe1-Xnix Aso, Guanghan Cao, Shuai Jiang, Xiao Lin, Cao Wang, Yuke Li, Zhi Ren, Qian Tao, Chunmu Feng, Jianhui Dai, Zhu-An Xu, Fu-Chun Zhang
Faculty of Engineering - Papers (Archive)
We have studied Ni-substitution effect in LaFe1−xNixAsO (0≤x≤0.1) by the measurements of x-ray diffraction, electrical resistivity, magnetic susceptibility, and heat capacity. The nickel doping drastically suppresses the resistivity anomaly associated with spin-density-wave ordering in the parent compound. Superconductivity emerges in a narrow region of 0.03≤x≤0.06 with the maximum Tc of 6.5 K at x=0.04, where enhanced magnetic susceptibility shows up. The upper critical field at zero temperature is estimated to exceed the Pauli paramagnetic limit. The much lowered Tc in comparison with LaFeAsO1−xFx system is discussed.
Subterahertz Josephson Plasma Emission In Layered High-T-C Superconducting Tunnel Junctions, Gustavo A. Alvarez, T Puzzer, Xiaolin Wang, Roger A. Lewis, Carey A. Freeth, S. X. Dou
Subterahertz Josephson Plasma Emission In Layered High-T-C Superconducting Tunnel Junctions, Gustavo A. Alvarez, T Puzzer, Xiaolin Wang, Roger A. Lewis, Carey A. Freeth, S. X. Dou
Faculty of Engineering - Papers (Archive)
We investigated the emission of subterahertz frequency electromagnetic radiation from high-TC superconducting c-axis NdBa2Cu3O7−8/PrBa2Cu3O7−8/NdBa2Cu3O7−8 trilayer thin film tunneling junctions when external electric and magnetic fields are applied. The current-voltage characteristics under applied ab-plane magnetic fields H (up 8 T) exhibit well defined steps, Vn, such that eVn -hwp / (2n), where the plasma frequency wp-0.4 THz and n=1,2,3, . . . .. These steps may be interpreted using Josephson plasma dynamics. The applied voltage creates oscillating currents via the Josephson coupling energy EJ (EJ=hIJ /4e, where IJ is the Josephson current and h is Planck’s constant) and the charge energy …
Explanation Of Magnetic Behavior In Ru-Based Superconducting Ferromagnets, Rashmi Nigam, Alexey V. Pan, S X. Dou
Explanation Of Magnetic Behavior In Ru-Based Superconducting Ferromagnets, Rashmi Nigam, Alexey V. Pan, S X. Dou
Faculty of Engineering - Papers (Archive)
We have investigated RuSr2Eu1.5Ce2O10 (Ru-1222) and RuSr2EuCu2O8 (Ru-1212) samples by using x-ray diffraction, scanning electron microscopy, dc magnetization, ac susceptibility, and resistivity measurements. Based on the results obtained, we propose an explanation of the magnetic behaviour of the Ru-based systems. Our model is capable of describing controversial observations of multiple magnetic transitions on temperature dependent dc magnetization measurements as well as the reentrance of irreversibility in hysteresis ≤200K. The experimental results suggest that Ru-based samples always contain a small amount of at least one additional magnetic phase with …
Effects Of Sintering Atmosphere On The Superconducting Properties Of Sic Doped Bulk Mgb2 Superconductor, Sihai Zhou, Alexey V. Pan, Yun Zhang, S. X. Dou
Effects Of Sintering Atmosphere On The Superconducting Properties Of Sic Doped Bulk Mgb2 Superconductor, Sihai Zhou, Alexey V. Pan, Yun Zhang, S. X. Dou
Faculty of Engineering - Papers (Archive)
A study was conducted to investigate the effects of the sintering atmosphere on the superconducting properties of SiC doped MgB2 superconductors. Four different purity Ar gases were chosen as the sintering atmosphere for making bulk samples. It was found that the impurities in the Ar gas resulted in different leves of MgO in the resultant MgB2 superconductors. Superconducting properties, such as the critical temperature (Tc), critical current density (Jc) and upper critical field (Hc2) were affected by the impurity phase inside the samples. Sample phase composition and morphology were analysed to explain the effect of the sintering atmosphere on the …
Phase Transformation And Superconducting Properties Of Mgb2 Using Ball-Milled Low Purity Boron, Xun Xu, Jung Ho Kim, Md. Shahriar-Al Hossain, Jinsoo Park, Yue Zhao, S. X. Dou, Wai Kong Yeoh, M Rindfleisch, M Tomsic
Phase Transformation And Superconducting Properties Of Mgb2 Using Ball-Milled Low Purity Boron, Xun Xu, Jung Ho Kim, Md. Shahriar-Al Hossain, Jinsoo Park, Yue Zhao, S. X. Dou, Wai Kong Yeoh, M Rindfleisch, M Tomsic
Faculty of Engineering - Papers (Archive)
MgB2 samples were prepared by using 96% boron (B) powder with strong crystalline phase that had been ball milled for various times. We observed samples that contained ball-milled 96% B in comparison with one made from as-supplied commercial 96% B, with the results showing a significant enhancement in the high field critical current density (Jc) due to small grain size and better reactivity. Specifically, many grain boundaries for MgB2 could be acting as strong flux pinning centers. Based on Rowell connectivity analysis, when the ball-milling time increased, the connectivity factor, described as the active cross-sectional …
Effect Of Boron Powder Purity On Superconducting Properties Of Bulk Mgb2, Xun Xu, Dayse Dos Santos, Jung Ho Kim, Wai Kong Yeoh, Meng J. Qin, Konstantin K. Konstantinov, S. X. Dou
Effect Of Boron Powder Purity On Superconducting Properties Of Bulk Mgb2, Xun Xu, Dayse Dos Santos, Jung Ho Kim, Wai Kong Yeoh, Meng J. Qin, Konstantin K. Konstantinov, S. X. Dou
Faculty of Engineering - Papers (Archive)
In order to study the influence of the amorphous Boron powder on the superconducting properties, MgB2 bulk samples were prepared using 96% and 99% pure commercial Boron powder as well as 92% commercial Boron powder after purification process. The results showed that the original 96% and the purified 92% powders have larger particle size compared to the pure 99% Boron powder, which leads to reduce magnetic critical current densities. In order to get higher performance MgB2, the purified low grade Boron powder need further control of their microstructure such as smaller particle size to enhance flux pinning from the grain …
Impact Of Sintering Temperature On The Physical Properties Of The Superconducting Ferromagnet: Rusr2eu1.5ce0.5cu2o10, Rashmi Nigam, Alexey V. Pan, S X. Dou
Impact Of Sintering Temperature On The Physical Properties Of The Superconducting Ferromagnet: Rusr2eu1.5ce0.5cu2o10, Rashmi Nigam, Alexey V. Pan, S X. Dou
Faculty of Engineering - Papers (Archive)
We report the influence of the sintering temperature on the electromagnetic behavior for the RuSr2Eu1.5Ce0.5Cu2O10 material, in which superconductivity and ferromagnetism coexist. The inadequate heat treatment results in the coexistence of the secondary Ru-1212 phase along with the dominant Ru-1222 phase. The presence of two phases leads to the magnetic superposition of the signals from both phases, which results in the observation of a small peak around 120–130 K. In the pure Ru-1222 no such magnetic anomaly is observed. In addition, the impure samples exhibit a double step superconductivity transition. In …
Superconducting Properties Of Mgb2: Polycarbosilane Versus Conventional Nano-Sic Doping, Olga V. Shcherbakova, Alexey V. Pan, David Wexler, S. X. Dou
Superconducting Properties Of Mgb2: Polycarbosilane Versus Conventional Nano-Sic Doping, Olga V. Shcherbakova, Alexey V. Pan, David Wexler, S. X. Dou
Faculty of Engineering - Papers (Archive)
The effect of polycarbosilane (PCS) doping on the superconducting properties of MgB2 was systematically investigated. Highly reactive C and Si appeared after PCS decomposition facilitating incorporation of C into the MgB2 lattice, as well as the reaction between Si and Mg, resulting in formation of a large number of small Mg2Si particles within MgB2 grains. C-substitution induced crystal lattice defects and impurities act as strong pinning centers, significantly improving Jc(Ba) performance in the high field region. The differences in the effects of SiC and PCS doping have been studied and are described to the structural transformation that occurs in MgB2 …
Effect Of Boron Powder Purity On Superconducting Properties Of Mgb2, Xun Xu, Meng J. Qin, Konstantin K. Konstantinov, Dayse Dos Santos, Wai Kong Yeoh, Jung Ho Kim, S. X. Dou
Effect Of Boron Powder Purity On Superconducting Properties Of Mgb2, Xun Xu, Meng J. Qin, Konstantin K. Konstantinov, Dayse Dos Santos, Wai Kong Yeoh, Jung Ho Kim, S. X. Dou
Faculty of Engineering - Papers (Archive)
The effect of the properties of starting boron powders on the superconducting properties of MgB2 has been studied. The 92% and 96% pure powders produce lower surface reactivity and larger particle size than the 99% boron powder, as can be seen from Brunauer–Emmett–Teller (BET) and scanning electron microscopy (SEM) results, indicating that the low purity powders cannot be used to archive the same superconducting properties as those of samples made from pure 99% boron powder. However, the purity of 92% and 96% boron powders can be improved by using a simple chemical process, leading to enhanced magnetic critical current …