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Articles 1 - 12 of 12
Full-Text Articles in Physical Sciences and Mathematics
Reaction Method Control Of Impurity Scattering In C-Doped Mgb2: Proving The Role Of Defects Besides C Substitution Level, S K. Chen, K Y. Tan, A S. Halim, X Xu, K S. B De Silva, W K. Yeoh, S X. Dou, A Kursumovic, J L. Macmanus-Driscoll
Reaction Method Control Of Impurity Scattering In C-Doped Mgb2: Proving The Role Of Defects Besides C Substitution Level, S K. Chen, K Y. Tan, A S. Halim, X Xu, K S. B De Silva, W K. Yeoh, S X. Dou, A Kursumovic, J L. Macmanus-Driscoll
Shi Xue Dou
In this study, Si and C were incorporated into polycrystalline MgB2 via in situ reaction of Mg and B with either SiC or with separate Si and C (Si+C). The electrical transport and magnetic properties of the two series of samples were compared. The corrected resistivity at 40K, pA(40K), is higher for the SiC reacted samples regardless of carbon (C) substitution level, indicating larger intragrain scattering because of the simultaneous reaction between Mg and SiC and carbon substitution during the formation of MgB2. In addition, because of the cleaner reaction route for the SiC reacted samples, the calculated active area …
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.
Lanthanum Doped Multiferroic Dyfeo3: Structural And Magnetic Properties, Yi Du, Zhenxiang Cheng, Xiaolin Wang, S X. Dou
Lanthanum Doped Multiferroic Dyfeo3: Structural And Magnetic Properties, Yi Du, Zhenxiang Cheng, Xiaolin Wang, S X. Dou
Shi Xue Dou
Lanthanum doped multiferroic DyFeO3 was synthesized by solid state reaction. X-ray diffraction and refinement show that the lattice parameters of Dy1−xLaxFeO3 increase linearly with the La content. Raman spectroscopy reveals that the short-range force constant in Dy1−xLaxFeO3 is decreased by La3+ ion substitution. The spin reorientation phase transition temperature (TSRPT) is observed to decrease along with the doping level. The antiferromagnetic ordering temperature TN of Fe3+ ions is depressed with increasing doping level. Both decreasing TSRPT and decreasing TN indicate that Fe–Dy and Fe–Fe interactions are weakened by La substitution. It is found that the electron configuration of Fe3+ is …
Superconducting Properties Of Carbonaceous Chemical Doped Mgb2, Wenxian Li, S X. Dou
Superconducting Properties Of Carbonaceous Chemical Doped Mgb2, Wenxian Li, S X. Dou
Shi Xue Dou
The discovery of superconductivity in magnesium diboride (MgB2: 39 K, in January 2001) (Nagamatsu et al., 2001) has generated enormous interest and excitement in the superconductivity community and the world in general, but especially among researchers into superconductivity in non-oxide and boron related compounds.
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
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
Shi Xue Dou
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 et …
Structure, Ferroelectric Properties, And Magnetic Properties Of The La-Doped Bismuth Ferrite, Zhenxiang Cheng, Aihua Li, Xiaolin Wang, S X. Dou, Kiyoshi Ozawa, Hideo Kimura, S Zhang, Thomas R. Shrout
Structure, Ferroelectric Properties, And Magnetic Properties Of The La-Doped Bismuth Ferrite, Zhenxiang Cheng, Aihua Li, Xiaolin Wang, S X. Dou, Kiyoshi Ozawa, Hideo Kimura, S Zhang, Thomas R. Shrout
Shi Xue Dou
Bi1-xLaxFeO3 ceramics with x=0, 0.1, 0.2, and 0.3 have been synthesized by solid state reaction, starting from metal oxides. A series of structure transformations is found to depend upon the doping level. Below 10% La doping, Bi1-xLaxFeO3 maintains the rhombohedral structure of BiFeO3. However, for Bi0.8La0.2FeO3 and Bi0.7La0.3FeO3, the structures change to the orthorhombic and tetragonal, respectively. La doping significantly reduces electric leakage and leads to successful observation of electrical polarization hysteresis loops. Doping with La also enhances the ferromagnetic moment, due to the broken cycloid spin structure caused by the changes in the crystalline structure.
Flux Pinning And Vortex Transitions In Doped Bafe2as2 Single Crystals, S R. Ghorbani, X L. Wang, M Shabazi, S X. Dou, K Y. Choi, C T. Lin
Flux Pinning And Vortex Transitions In Doped Bafe2as2 Single Crystals, S R. Ghorbani, X L. Wang, M Shabazi, S X. Dou, K Y. Choi, C T. Lin
Shi Xue Dou
The vortex liquid-to-glass transition has been studied in Ba0.72K0.28Fe2As2 (BaK-122), Ba(Fe0.91Co0.09)2As2(BaCo-122), and Ba(Fe0.95Ni0.05)2As2(BaNi-122) single crystal with superconducting transition temperature, Tc=31.7, 17.3, and 18 K, respectively, by magnetoresistance measurements. For temperatures below Tc, the resistivity curves were measured in magnetic fields within the range of 0≤B≤13 T, and the pinning potential was scaled according to a modified model for vortex liquid resistivity. Good scaling of the resistivity q(B, T) and the effective pinning energy U0(B,T) were obtained. The vortex state is three-dimensional at temperatures lower than a characteristic temperature T*. The vortex phase diagram was determined based on the evolution of …
Band Structures, Magnetic Properties, And Enhanced Magnetoresistance In The High Pressure Phase Of Gd And Y Doped Two-Dimensional Perovskite Sr2coo4 Compounds, Xiaolin Wang, E Takayama-Muromachi, S X. Dou, Zhenxiang Cheng
Band Structures, Magnetic Properties, And Enhanced Magnetoresistance In The High Pressure Phase Of Gd And Y Doped Two-Dimensional Perovskite Sr2coo4 Compounds, Xiaolin Wang, E Takayama-Muromachi, S X. Dou, Zhenxiang Cheng
Shi Xue Dou
The authors present their studies on the band structures and on the magnetic and magnetotransport properties of the high pressure phase of Sr2-xRExCoO4 [rare earth (RE)=Gd and Y, x=0.1-0.5] compounds which were synthesized by a high pressure and high temperature technique. The authors found that as x increases, the magnetoresistance {(PH-P0)/p0} increases up to -17% at 5 K and 7 T, which is 2.5 times higher than that for undoped Sr2CoO4, although the ferromagnetic transition drops from 255 to 200 K for the Gd doping with x=0.3. The saturation moments at low temperature are significantly enhanced for the Gd doped …
Magnetic And Transport Properties Of Transition Metal Doped Polycrystalline In2o3, Germanas Peleckis, Xiaolin Wang, S X. Dou
Magnetic And Transport Properties Of Transition Metal Doped Polycrystalline In2o3, Germanas Peleckis, Xiaolin Wang, S X. Dou
Shi Xue Dou
Synthesis and characterization of transition metal (TM)-doped In 2O3 oxide is reported. Most of the samples were found to be paramagnetic, and only Ye and Cr co-doped sample showed as light trace of ferromagnetism at 300 K with saturation magnetization M s = 0.35 emug/g. Measured transport properties revealed significant differences in transport among the samples. The absolute value of electrical resistivity for the In1.8Fe0.1Mn0.1O3 sample at 300 K was rho= 9.4 x 103 Omega middot cm, while In1.8Fe0.1Cr0.1O3 had rho = 62 Omega middot cm at the same temperature. Furthermore, magnetoresistance (MR) studies of In1.8Fe0.1Cr0.1O3 showed that the sign …
Phase Formation And Magnetotransport Of Alkali Metal Doped Na0.75coo2 Thermoelectric Oxide, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou, H Yamauchi, M Karppinen
Phase Formation And Magnetotransport Of Alkali Metal Doped Na0.75coo2 Thermoelectric Oxide, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou, H Yamauchi, M Karppinen
Shi Xue Dou
Synthesis and characterization of bulk NaxCoO2 samples substituted by K and Rb is reported. Phase formation studies revealed a narrow stable region for Na-alkali metal-Co system. Whisker and platelike single crystalline structures have been found to form on the surface of the pellets in case of K doping. All samples were metallic and no characteristic anomaly in R-T curves was observed for Rb doped sample. Magnetoresistance measured has a pronounced positive response only for K-doped and pure NaxCoO2 phases, reaching 11% and 7% at 5 K temperature, respectively.
Strong Competition Between The Delta L And Delta T-C Flux Pinning Mechanisms In Mgb2 Doped With Carbon Containing Compounds, Shaban R. Ghorbani, Xiaolin Wang, Md S. Hossain, Qiwen Yao, S X. Dou, Sung-Ik Lee, K C. Chung, Y K. Kim
Strong Competition Between The Delta L And Delta T-C Flux Pinning Mechanisms In Mgb2 Doped With Carbon Containing Compounds, Shaban R. Ghorbani, Xiaolin Wang, Md S. Hossain, Qiwen Yao, S X. Dou, Sung-Ik Lee, K C. Chung, Y K. Kim
Shi Xue Dou
The transport and magnetic properties of 10 wt % malic acid and 5 wt % nanocarbon doped MgB2 have been studied by measuring the resistivity (p), critical current density (jc), connectivity factor (AF), irreversibility field (Hirr), and upper critical field (Hc2). The pinning mechanisms are studied in terms of the collective pinning model. It was found that both mean free path (δl) and critical temperature (δTc) pinning mechanisms coexist in both doped MgB2. For both the malic acid and nanocarbon doped samples, the temperature dependence of the crossover field, which separates the single vortex and the small bundle pinning regime, …
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
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
Shi Xue Dou
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 temperature, however, there is evidence for δTc pinning, …