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Full-Text Articles in Engineering
The Effects Of Annealing Temperature On The In-Field Jc And Surface Pinning In Silicone Oil Doped Mgb2 Bulks And Wires, M S. Hossain, A Motaman, O Cicek, H Agil, E Ertekin, A Gencer, Xiaolin Wang, S X. Dou
The Effects Of Annealing Temperature On The In-Field Jc And Surface Pinning In Silicone Oil Doped Mgb2 Bulks And Wires, M S. Hossain, A Motaman, O Cicek, H Agil, E Ertekin, A Gencer, Xiaolin Wang, S X. Dou
Shi Xue Dou
No abstract provided.
In-Field Jc Improvement By Oxygen-Free Pyrene Gas Diffusion Into Highly Dense Mgb2 Superconductor, Minoru Maeda, Jung Ho Kim, Y Zhao, Yoon-Uk Heo, K Takase, Y Kubota, C Moriyoshi, F Yoshida, Y Kuroiwa, S X. Dou
In-Field Jc Improvement By Oxygen-Free Pyrene Gas Diffusion Into Highly Dense Mgb2 Superconductor, Minoru Maeda, Jung Ho Kim, Y Zhao, Yoon-Uk Heo, K Takase, Y Kubota, C Moriyoshi, F Yoshida, Y Kuroiwa, S X. Dou
Shi Xue Dou
Oxygen-free pyrene gas as a carbon (C) dopant was delinked and incorporated into highly dense MgB2 structure via a gas phase diffusion method. The technique offers the advantages that molecular C is homogeneously distributed into MgB2 and substituted at the boron sites without any severe deterioration of grain connectivity. The C substitution causes a significant shrinkage of the a-lattice parameter and an increase in the lattice strain, resulting in high disorder. The introduction of structural disorder as a result of C doping leads to a considerable enhancement of the in-field critical current density (Jc) and upper critical field.
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 …
Increased Superconductivity For Cnt Doped Mgb2 Sintered In 5t Pulsed Magnetic Field, Wenxian Li, Ying Li, Rong Hua Chen, Rong Zeng, Lin Lu, Yun Zhang, Michael Tomsic, Matthew Rindfleisch, S. X. Dou
Increased Superconductivity For Cnt Doped Mgb2 Sintered In 5t Pulsed Magnetic Field, Wenxian Li, Ying Li, Rong Hua Chen, Rong Zeng, Lin Lu, Yun Zhang, Michael Tomsic, Matthew Rindfleisch, S. X. Dou
Shi Xue Dou
The superconductivity of carbon nanotube (CNT) doped MgB2 sintered in pulsed magnetic field (PMF) was investigated with Raman scattering measurements and Raman spectral fit analysis. Although the carbon (C) substitution for the boron (B) is increased for the sample sintered in PMF, its superconductivity is advanced comparing with the sample sintered without PMF. The improved critical transition temperature, Tc, is attributed to the strengthening of the electron-phonon coupling (EPC) in MgB2, as reflected by the broadened E 2g mode in the Raman spectra, because the carbon atoms are homogeneously distributed in the boron planes.
Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou
Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou
Shi Xue Dou
The critical behaviour of Mn0.94Nb0.06CoGe alloy around the paramagnetic-ferromagnetic phase transition was studied based on the field dependence on magnetic entropy change. By using the obtained exponents, the modified Arrott plot is consistent with that by using conventional method. These critical exponents are confirmed by the Widom scaling relation. Based on these critical exponents, the magnetization, field and temperature data around Tc collapse into two curves obeying the single scaling equation MðH; e)¼ebf6(H/ebþc). The calculated critical exponents not only obey the scaling theory but also anastomose the deduced results from the Kouvel-Fisher method [J. S. Kouvel and M. E. Fisher, …
Magnetic Field Dependent Neutron Powder Diffraction Studies Of Ru0.9sr2ycu2.1o7.9, Rashmi Nigam, Alexey V. Pan, S. X. Dou, S J. Kennedy, A J Studer, N Stuesser
Magnetic Field Dependent Neutron Powder Diffraction Studies Of Ru0.9sr2ycu2.1o7.9, Rashmi Nigam, Alexey V. Pan, S. X. Dou, S J. Kennedy, A J Studer, N Stuesser
Shi Xue Dou
Temperature and magnetic field dependent neutron diffraction has been used to study the magnetic order in Ru0.9Sr2YCu2.1O7.9. The appearance of (1/2, 1/2, 1/2), (1/2, 1/2, 3/2), and (1/2, 1/2, 5/2) peaks below TM = 140 K manifests the antiferromagnetic order. Neutron diffraction patterns measured in applied magnetic fields from 0 to 6 T show the destruction of the antiferromagnetic order with increasing field. There is no evidence of spontaneous or field-induced long range ferromagnetic order. This latter result contradicts the vast majority of other experimental observations for this system.
Competition Between The Crystal Field And The Exchange Field In Er3+ Doped Ndmno3, Fang Hong, Zhenxiang Cheng, Xiaolin Wang, S X. Dou
Competition Between The Crystal Field And The Exchange Field In Er3+ Doped Ndmno3, Fang Hong, Zhenxiang Cheng, Xiaolin Wang, S X. Dou
Shi Xue Dou
A careful investigation of specific heat shows that the ground state splitting of Nd3þ has been modified by the Er3þ doping, as it shows a nonlinear dependence on the Er3þ doping rate, due to the competition between the crystal field and the exchange field. This competition could be further confirmed by the anomalies in the magnetic entropy and the ground state splitting found in Nd0.9Er0.1MnO3. On the contrary, the ground state splitting of Er3þ has a linear dependence on the doping rate, indicating its stronger dependence on the crystal field rather than the exchange field.
Upper Critical Field And Thermally Activated Flux Flow In Lafeaso1-Xfx, Mahboobeh Shahbazi, Xiaolin Wang, C Shekhar, O N. Srivastava, Z W. Lin, J G. Zhu, S. X. Dou
Upper Critical Field And Thermally Activated Flux Flow In Lafeaso1-Xfx, Mahboobeh Shahbazi, Xiaolin Wang, C Shekhar, O N. Srivastava, Z W. Lin, J G. Zhu, S. X. Dou
Shi Xue Dou
The magneto-resistance, critical current density, Jc, upper critical field, Hc2, and flux pinning properties of LaFeAsO1−xFx superconductors were investigated systematically by magnetic and magneto-transport measurements in the fields up to 13 T over a temperature range of 5–35 K. It was found that the Hc2 increased with increasing fluorine concentration up to x ≤ 0.15, while with higher fluorine doping, Hc2 decreased. A peak effect in the Jc as a function of field was observed at T Uo, scales as Uo/kB ∝ B−n with n = 0.13 for B n =− 0.68 for B > 1 T for LaFeAsO0.85F0.15.
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 …
A Sign Of Field-Induced First Order Magnetic State Transition And Giant Reversible Magnetocaloric Effect In Cobalt Hydroxide Nanosheets, Precious Shamba, Rong Zeng, J Q Wang, S X. Dou
A Sign Of Field-Induced First Order Magnetic State Transition And Giant Reversible Magnetocaloric Effect In Cobalt Hydroxide Nanosheets, Precious Shamba, Rong Zeng, J Q Wang, S X. Dou
Shi Xue Dou
We report the synthesis of β−Co(OH)2 nanosheets using microwave assisted hydrothermal and conventional chemical reaction methods. A magnetic transition at an onset temperature, T1 ~ 96 K, and a sign of antiferromagnetic state transition at the Néel temperature, TN=9~10 K, can be determined from M-T curves and M-H curves magnetic properties investigation. It is found that a sign of field-induced first order transition below 9 K, act as a role of reversing the magnetocaloric effect from negative to positive value. The large reversible magnetic-entropy change (∆SM) of 17 J/kg K around 11 K for a field change of 5 T …
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
Shi Xue Dou
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 the width was …
Influence Of Disorder On The In-Field Jc Of Mgb2 Wires Using Highly Active Pyrene, Jung Ho Kim, Xun Xu, Md. Shahriar-Al Hossain, Dongqi Shi, Yue Zhao, Xiaolin Wang, S. X. Dou, S. Choi, T. Kiyoshi
Influence Of Disorder On The In-Field Jc Of Mgb2 Wires Using Highly Active Pyrene, Jung Ho Kim, Xun Xu, Md. Shahriar-Al Hossain, Dongqi Shi, Yue Zhao, Xiaolin Wang, S. X. Dou, S. Choi, T. Kiyoshi
Shi Xue Dou
In this work, we report on significantly enhanced critical current density (Jc) in MgB2 superconductor that was easily obtained by doping with a hydrocarbon, highly active pyrene (C16H10), and using a sintering temperature as low as ∼ 600 °C. The processing advantages of the C16H10 additive include production of a highly active carbon (C) source, an increased level of disorder, and the introduction of small grain size, resulting in enhancement of Jc.
Giant Magnetic Entropy Change In Colossal Magnetoresistance In La0.7ca0.3mno3 Material In Low Field, Jyotish Debnath, Rong Zeng, Jung Ho Kim, S X. Dou
Giant Magnetic Entropy Change In Colossal Magnetoresistance In La0.7ca0.3mno3 Material In Low Field, Jyotish Debnath, Rong Zeng, Jung Ho Kim, S X. Dou
Shi Xue Dou
The structural, magnetic, and magnetocaloric properties of the manganite La0.7Ca0.3MnO3 have been studied. Change in the giant magnetic entropy was observed without any noticeable magnetic hysteresis but with small thermal hysteresis losses. We observed a first order magnetic phase transition around 251 K. The magnetic entropy change observed in this work is estimated to be 5.27 J/kg K for field changes from 0 to 1.5 T based on magnetization measurements. This value is about twice as large as those for other perovskite manganites and is even larger than for Gd-based magnetic materials at low fields. In addition, the entropy change …
Silicon Oil: A Cheap Liquid Additive For Enhancing In-Field Critical Current Density In Mgb2, Xiaolin Wang, Zhenxiang Cheng, S X. Dou
Silicon Oil: A Cheap Liquid Additive For Enhancing In-Field Critical Current Density In Mgb2, Xiaolin Wang, Zhenxiang Cheng, S X. Dou
Shi Xue Dou
In this work, the authors report on significant flux pinning enhancement in MgB2 that has been easily obtained using a liquid additive, silicon oil. MgB2 bulk samples with 0 up to 30 wt % silicon oil added were prepared by an in situ reaction. Results showed that the Si and C released from the decomposition of the silicon oil formed Mg2Si and substituted into B sites, respectively. Increasing the amount of the Si oil up to 15 wt % has resulted in the reduction of the lattice parameters, as well as Tc and R(300 K)/R(Tc) values, accompanied by a significant …
Observation Of Field-Induced Polarization Of Valleys In P-Type Sb 2te 3 Single Crystals, Z J. Yue, C B. Zhu, S X. Dou, Xiaolin Wang
Observation Of Field-Induced Polarization Of Valleys In P-Type Sb 2te 3 Single Crystals, Z J. Yue, C B. Zhu, S X. Dou, Xiaolin Wang
Shi Xue Dou
A flow of carriers along the c axis is extremely sensitive to the orientation of an in-plane magnetic field due to in-plane mass anisotropy in layered compounds. Based on this mechanism, a rotatable in-plane magnetic field has been applied as a valley valve to tune the contribution of each valley in p-type Sb2Te3 bulk single crystals to the total conductivity and interlayer magnetoresistance (MR). A valley-polarized current is generated, and the angular-dependent interlayer MR of up to 160% represents strong anisotropy. There are six inequivalent peaks over all temperature and magnetic field ranges. The giant MR results from the intravalley …
Enhancement Of The In-Field Jc Of Mgb2 Via Sicl4 Doping, Xiaolin Wang, S X. Dou, Md S. Hossain, Zhenxiang Cheng, X.Z Liao, Shaban R. Ghorbani, Qiwen Yao, Jung Ho Kim, Tania M. Silver
Enhancement Of The In-Field Jc Of Mgb2 Via Sicl4 Doping, Xiaolin Wang, S X. Dou, Md S. Hossain, Zhenxiang Cheng, X.Z Liao, Shaban R. Ghorbani, Qiwen Yao, Jung Ho Kim, Tania M. Silver
Shi Xue Dou
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 …
Angular Dependence Of Pinning Potential, Upper Critical Field, And Irreversibility Field In Underdoped Bafe1.9co0.1as2 Single Crystal, Mahboobeh Shahbazi, Xiaolin Wang, S R. Ghorbani, S. X. Dou, K Y. Choi
Angular Dependence Of Pinning Potential, Upper Critical Field, And Irreversibility Field In Underdoped Bafe1.9co0.1as2 Single Crystal, Mahboobeh Shahbazi, Xiaolin Wang, S R. Ghorbani, S. X. Dou, K Y. Choi
Shi Xue Dou
Underdoped BaFe1.9Co0.1As2 single crystal was studied by angular dependence of magneto-transport at fields up to 13 T over a wide range of temperature. Our results show that pinning potential, Uo, decreases slightly for h45 and remains constant for h45, while the upper critical field, Hc2, and the irreversibility field, Hirr, increase with h. According to anisotropic Ginzburg-Landau theory, the anisotropy was determined by scaling the resistivity under different magnetic fields below the superconducting critical temperature, Tc. Anisotropy, C, in the underdoped crystal is found to be temperature dependent and decreases from 2.1 to 1.8 for as T is reduced from …