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Full-Text Articles in Engineering
Capacitive Behavior Of Latex/Single-Wall Carbon Nanotube Stretchable Electrodes, Hyeon Taek Jeong, Byung Kim, Robert Gorkin Iii, Michael J. Higgins, Gordon G. Wallace
Capacitive Behavior Of Latex/Single-Wall Carbon Nanotube Stretchable Electrodes, Hyeon Taek Jeong, Byung Kim, Robert Gorkin Iii, Michael J. Higgins, Gordon G. Wallace
Robert Gorkin III
In this report single-wall carbon nanotubes (SWNTs) were coated onto latex using spray coating to produce a stretchable electrode. The electrochemical properties of the electrode were determined using cyclic voltammetry and electrochemical impedance spectroscopy and galvanostatic charge/discharge tests were also carried out. The impedance and charge/discharge curves of the latex/SWNTs electrode showed good capacitive behavior even after repetitive stretching to 100% strain. The highest capacitance value obtained for the unstretched SWNTs electrode was 119 F g−1 in 1 M Na2SO4 at 5 mV s−1. After the 100th stretch ≈ 80% of the original capacitance value was retained.
Novel Modulation And Control Strategy For Five-Level Anpc Converter With Unbalanced Dc Voltage Applied To A Single-Phase Grid Connected Pv System, Hamid R. Teymour, Danny Sutanto, Kashem M. Muttaqi, Phil Ciufo
Novel Modulation And Control Strategy For Five-Level Anpc Converter With Unbalanced Dc Voltage Applied To A Single-Phase Grid Connected Pv System, Hamid R. Teymour, Danny Sutanto, Kashem M. Muttaqi, Phil Ciufo
Dr Philip Ciufo
This paper proposes a new control strategy and a novel modulation technique for a grid-connected photo-voltaic (PV) system using a single-phase five-level flying capacitor (FC) based active-neutral-point-clamped (ANPC) converter. The proposed modulator can control the FC voltage to follow the requested reference value and simultaneously generate the required ac output voltage regardless of the values of the dc capacitor voltages of the converter. By implementing this method, smaller values of dc-link and flying capacitors can be used even in applications that could experience ripple or transient in the capacitors voltage. In the grid-connected single-phase five-level ANPC, where the capacitors can …
Effects Of Normal Stress On Water Flow Through A Single Roughwalled Rock Joint, Z Zhang, B Indraratna, C Kumara, Jan Anton Nemcik, W Gale
Effects Of Normal Stress On Water Flow Through A Single Roughwalled Rock Joint, Z Zhang, B Indraratna, C Kumara, Jan Anton Nemcik, W Gale
Buddhima Indraratna
Water ingress to underground openings is one of the major concerns in mining and tunnelling, because, rock joints provide natural seepage paths for groundwater flow. To study the water flow through deformable rock joints, triaxial tests with water flow were conducted under various confining stress levels (0.7-5.0 MPa). Two tests were performed on fully mated fracture specimens, and three tests were performed on a non-mated specimen where the fractured surfaces were displaced by 2.0 mm at the start of the test. The results show that the volumetric flow rate decreases with the increase in the normal stress, but the decreasing …
Secure Single Sign-On Schemes Constructed From Nominative Signatures, Jingquan Wang, Guilin Wang, Willy Susilo
Secure Single Sign-On Schemes Constructed From Nominative Signatures, Jingquan Wang, Guilin Wang, Willy Susilo
Professor Willy Susilo
Single Sign-on (SSO) allows users to only log on once and then access different services via automatic authentication by using the same credential. However, most existing SSO schemes do not satisfy security notions or require a high trust level on a trusted third party (TTP), even though SSO has become popular in new distributed systems and computer networks. Motivated by this fact, we formalise a new security model of single sign-on, which not only satisfies strong security notions but also has a low trust level on TTP. We then propose a generic construction of SSO from nominative signatures, and present …
Giant Interlayer Magnetoresistances And Strong Anisotropy In P-Type Sb2te3 Single Crystals, Zengji Yue, Xiaolin Wang, S X. Dou
Giant Interlayer Magnetoresistances And Strong Anisotropy In P-Type Sb2te3 Single Crystals, Zengji Yue, Xiaolin Wang, S X. Dou
Shi Xue Dou
Anisotropic interlayer magneto-transport properties have been studied over a broad range of temperatures and magnetic fields in p-type Sb2Te3 single crystals. Giant interlayer magnetoresistance (MR) of up to 400% was observed, which exhibits quadratic field dependences in low fields and becomes linear at high fields without any trend towards saturation. The interlayer MR displays strong anisotropy and is attributable to the anisotropy of the Fermi surface. The observed giant anisotropic interlayer MR could find applications in p-type Sb2Te3 based magneto-electronic devices.
Flux Pinning Mechanism In Bafe1.9ni0.1as2 Single Crystals: Evidence For Fluctuation In Mean Free Path Induced Pinning, M Shahbazi-Manshadi, X L Wang, K Y Choi, S X. Dou
Flux Pinning Mechanism In Bafe1.9ni0.1as2 Single Crystals: Evidence For Fluctuation In Mean Free Path Induced Pinning, M Shahbazi-Manshadi, X L Wang, K Y Choi, S X. Dou
Shi Xue Dou
The flux pinning mechanism of BaFe1.9Ni0.1As2 superconducting crystals have been investigated systematically by magnetic measurements up to 13 T at various temperatures. The field dependence of the critical current density, Jc, was analysed within the collective pinning model. A remarkably good agreement between the experimental results and theoretical dl pinning curve is obtained, which indicates that pinning in BaFe1.9Ni0.1As2 crystal originates from spatial variation of the mean free path. Moreover, the normalized pinning force density, Fp, curves versus h1/4B/Birr (Birr is the irreversibility field) were scaled using the Dew-Hughes model. Analysis suggests that point pinning alone cannot explain the observed …
The Flux Pinning Mechanism, And Electrical And Magnetic Anisotropy In Fe1.04te0.6se0.4 Superconducting Single Crystal, Mahboobeh Shahbazi-Manshadi, Xiaolin Wang, S X. Dou, H Fang, C T. Lin
The Flux Pinning Mechanism, And Electrical And Magnetic Anisotropy In Fe1.04te0.6se0.4 Superconducting Single Crystal, Mahboobeh Shahbazi-Manshadi, Xiaolin Wang, S X. Dou, H Fang, C T. Lin
Shi Xue Dou
The temperature and magnetic field dependences of the magnetization and critical current density of Fe1.04Te0.6Se0.4 single crystals have been investigated, and the flux pinning mechanism has been analysed. The normalized pinning force (fp Fp/F p,max) vs. h(H/Hirr) curves, are scaled using the Dew-Hughes theory, f(h) ≈ hp(1 - h)q with p 1.35 and q 3.06. The angular dependence of the resistivity under different magnetic fields shows a dip-like structure, below the superconducting transition temperature. The anisotropic value of 2 was obtained using Ginzburg-Landau theory.
Giant Interlayer Magnetoresistances And Strong Anisotropy In P-Type Sb2te3 Single Crystals, Zengji Yue, Xiaolin Wang, S Dou
Giant Interlayer Magnetoresistances And Strong Anisotropy In P-Type Sb2te3 Single Crystals, Zengji Yue, Xiaolin Wang, S Dou
Zengji Yue
Anisotropic interlayer magneto-transport properties have been studied over a broad range of temperatures and magnetic fields in p-type Sb2Te3 single crystals. Giant interlayer magnetoresistance (MR) of up to 400% was observed, which exhibits quadratic field dependences in low fields and becomes linear at high fields without any trend towards saturation. The interlayer MR displays strong anisotropy and is attributable to the anisotropy of the Fermi surface. The observed giant anisotropic interlayer MR could find applications in p-type Sb2Te3 based magneto-electronic devices.
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
Zengji Yue
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 …
Giant And Anisotropic Magnetoresistances In P-Type Bi-Doped Sb 2te 3 Bulk Single Crystals, Z J. Yue, Xiaolin Wang, Y Du, S M. Mahboobeh, Frank F. Yun, Z X. Cheng, S. X. Dou
Giant And Anisotropic Magnetoresistances In P-Type Bi-Doped Sb 2te 3 Bulk Single Crystals, Z J. Yue, Xiaolin Wang, Y Du, S M. Mahboobeh, Frank F. Yun, Z X. Cheng, S. X. Dou
Zengji Yue
Antimony telluride (Sb2Te3) compounds are well known as excellent thermoelectric materials and have been recently confirmed as three-dimensional topological insulators. In this letter, we have investigated the anisotropic magneto-transport properties of p-type Bi-doped Sb2Te3 bulk single crystals over a broad range of temperatures, degrees and magnetic fields. Giant magnetoresistance (MR) of up to 230% was observed, which exhibits quadratic field dependences in low fields and becomes linear at high fields without any trend towards saturation. The giant MR also shows strong anisotropy with anisotropy ratio up to 210% in angle-dependent measurements. The giant MR might result from strong intervalley and …
Single Detector-Dual Scintillator Anti-Comptom Probes, Anatoly B. Rosenfeld, Michael L. Lerch, George J. Takacs, A Getkin, V Perevertailo
Single Detector-Dual Scintillator Anti-Comptom Probes, Anatoly B. Rosenfeld, Michael L. Lerch, George J. Takacs, A Getkin, V Perevertailo
Michael L.F. Lerch
Anti¬-Compton spectrometers have many applications in the fields of safeguards, medicine and security. One of the most important applications is in the location of low energy gamma sources in the presence of high-¬energy gamma background or the location of high-¬energy gamma radiation sources hidden within the same spread of radiation background. In most situations space constraints limit the application of large size detectors or classical anti¬-Compton spectrometers. We have designed a compact anti-¬Compton spectrometer based on a single chip, dual silicon photodetector optically coupled to isolated, annular scintillators. Preliminary room temperature testing with Csl(TI) and LYSO scintillators demon¬strate the readout …
Thermomechanical Behavior Of Nickel Base Single Crystal Superalloy Towards Understanding Of Weld Hot Cracking, S S. Babu, J M. Vitek, S A. David, M Murugananth
Thermomechanical Behavior Of Nickel Base Single Crystal Superalloy Towards Understanding Of Weld Hot Cracking, S S. Babu, J M. Vitek, S A. David, M Murugananth
Muruganant Marimuthu
"Thermomechanical responses of three single crystal superalloys were measured in between 600 and 1200 degrees C using a thermomechanical simulator. On-heating results showed no softening while testing below 1000 degrees C. In contrast, extensive softening was observed while testing above 1000 degrees C. This rapid softening is related to dissolution of gamma' precipitates. During on-cooling tests from 1300 degrees C, strength recovery of these samples occurred only below 900 degrees C. The delay in strength recovery is attributed to the extent of undercooling required for rapid decomposition of the gamma phase into mixture of gamma and gamma' phases."
Thermomechanical Testing Of Nickel Base Superalloy Single Crystals, S S. Babu, J M. Vitek, S A. David, M Murugananth
Thermomechanical Testing Of Nickel Base Superalloy Single Crystals, S S. Babu, J M. Vitek, S A. David, M Murugananth
Muruganant Marimuthu
Thermomechanical response of single crystal superalloys during weld heating and cooling will affect cracking behavior in the heat-affected-zone (HAZ) and weld-metal (WM) regions. Thermomechanical response of these superalloys will depend on the phase fractions of ordered am ma-prime precipitates in the am ma matrix. During weld heating, the am ma-prime precipitates will dissolve as they approach the solvus temperature and some liquation may occur in the interdendritic regions. On cooling, the single-phase gamma matrix will decompose to a mixture of am ma and am ma-prime phases. In this work we evaluated the strength, ductility and reduction in area as a …
Magnetic Properties In Polycrystalline And Single Crystal Ca-Doped Lacoo3, R Zeng, J C. Debnath, Dapeng Chen, P Shamba, Jianli Wang, S J. Kennedy, S J. Campbell, Tania M. Silver, S. X. Dou
Magnetic Properties In Polycrystalline And Single Crystal Ca-Doped Lacoo3, R Zeng, J C. Debnath, Dapeng Chen, P Shamba, Jianli Wang, S J. Kennedy, S J. Campbell, Tania M. Silver, S. X. Dou
Jianli Wang
Polycrystalline (PC) and single crystalline (SC) Ca-doped LaCoO3 (LCCO) samples with the perovskite structure were synthesized by conventional solid-state reaction and the floating-zone growth method. We present the results of a comprehensive investigation of the magnetic properties of the LCCO system. Systematic measurements have been conducted on dc magnetization, ac susceptibility, exchange-bias, and the magnetocaloric effect. These findings suggest that complex structural phases, ferromagnetic (FM), and spin-glass/cluster-spin-glass (CSG), and their transitions exist in PC samples, while there is a much simpler magnetic phase in SC samples. It was also of interest to discover that the CSG induced a magnetic field …
Magnetocapacitance Effect In Nonmultiferroic Yfe03 Single Crystal, Z X. Cheng, H Shen, J Xu, Peng Liu, S J. Zhang, Jianli Wang, Xiaolin Wang, S X. Dou
Magnetocapacitance Effect In Nonmultiferroic Yfe03 Single Crystal, Z X. Cheng, H Shen, J Xu, Peng Liu, S J. Zhang, Jianli Wang, Xiaolin Wang, S X. Dou
Jianli Wang
YFeO3 single crystal displays two relaxor-like dielectric relaxations, one at low temperature (170300 K) and one at high temperature (370520 K), which are attributed to the activation of electrons and oxygen vacancies, respectively. Above the temperature at which electrons are activated, the sample displays a large magnetocapacitance effect. Comparison of the impedance Cole-Cole plots measured with and without applied magnetic field reveals that the occurrence of magnetocapacitance effect is accompanied with an increasing in DC conductivity under magnetic field after the activation of electrons, which is explained by the enhancement of electron jumping in Fe2b-O-Fe3b chains by magnetic field. Thus …
Visualization Of Vortex Motion In Feas-Based Bafe1.9ni0.1as2 Single Crystal By Means Of Magneto-Optical Imaging, Zhi W. Lin, Yong Jian Li, Jian G. Zhu, Xiaolin Wang, S. X. Dou, Youguang Guo, Gang Lei, Yi Wang, Matthew Philips, Michael Cortie, Yan-Cheng Li, Ki-Young Choi, Xun Shi
Visualization Of Vortex Motion In Feas-Based Bafe1.9ni0.1as2 Single Crystal By Means Of Magneto-Optical Imaging, Zhi W. Lin, Yong Jian Li, Jian G. Zhu, Xiaolin Wang, S. X. Dou, Youguang Guo, Gang Lei, Yi Wang, Matthew Philips, Michael Cortie, Yan-Cheng Li, Ki-Young Choi, Xun Shi
Shi Xue Dou
Superconductivity has been found in newly discovered iron-based compounds. This paper studies the motion of magnetic vortices in BaFe1.9Ni0.1As2 single crystal by means of the magneto-optical imaging technique. A series of magneto-optical images reflecting magnetic flux distribution at the crystal surface were taken when the crystal was zero-field cooled to 10 K. The behavior of the vortices, including penetration into and expulsion from the single crystal with increasing and decreasing external fields, respectively, is discussed. The motion behavior is similar to that observed in high-Tc superconducting cuprates with strong vortex pinning; however, the …
Silicon/Single-Walled Carbon Nanotube Composite Paper As A Flexible Anode Material For Lithium Ion Batteries, Shulei Chou, Yue Zhao, Jiazhao Wang, Zhixin Chen, Hua-Kun Liu, S. X. Dou
Silicon/Single-Walled Carbon Nanotube Composite Paper As A Flexible Anode Material For Lithium Ion Batteries, Shulei Chou, Yue Zhao, Jiazhao Wang, Zhixin Chen, Hua-Kun Liu, S. X. Dou
Shi Xue Dou
Flexible silicon/single-walled carbon nanotube (Si/SWCNT) composite paper was prepared using the pulsed laser deposition (PLD) method to deposit Si onto SWCNT paper. In the composite, Si mainly shows nanoworm-like morphology. Increasing deposition time results in an increased amount of Si microspheres. Electrochemical measurements show that the capacity of the composite paper is improved by the presence of Si. The Si/SWCNT composite with only 2.2% Si shows a capacity of 163 mA h g−1 at a current density of 25 mA g−1 up to 50 cycles, which is more than 60% improvement of the capacity of pristine CNT paper. The Si …
Anisotropic And Excellent Magnetocaloric Properties Of La 0.7ca0.3mno3 Single Crystal With Anomalous Magnetization, J.C Debnath, Rong Zeng, Jung Ho Kim, Dapeng Chen, S X. Dou
Anisotropic And Excellent Magnetocaloric Properties Of La 0.7ca0.3mno3 Single Crystal With Anomalous Magnetization, J.C Debnath, Rong Zeng, Jung Ho Kim, Dapeng Chen, S X. Dou
Shi Xue Dou
Magnetic properties and the magnetocaloric effect (MCE) have been investigated in La0.7Ca0.3MnO3 single crystal with applied field along both the ab-plane and the c-direction. Due to the magnetocrystalline anisotropy, the crystal exhibits anisotropy in the MCE. Upon application of a 5 T field, the magnetic entropy changes (SM), reaching values of 7.668 J/(kg K) and 6.412 J/(kg K) for both the ab-plane and the c-direction, respectively. A magnetic entropy change of 3.3 J/(kg K) was achieved for a magnetic field change of 1.5 T at the Curie temperature, TC = 245 K. Due to the absence of grains in the …
Effect Of Frozen Spin On The Magnetocaloric Property Of La0.7ca0.3coo3 Polycrystalline And Single Crystal Samples, J C. Debnath, R Zeng, J H. Kim, P Shamba, Dapeng Chen, S X. Dou
Effect Of Frozen Spin On The Magnetocaloric Property Of La0.7ca0.3coo3 Polycrystalline And Single Crystal Samples, J C. Debnath, R Zeng, J H. Kim, P Shamba, Dapeng Chen, S X. Dou
Shi Xue Dou
Polycrystalline (PC) and single crystalline (SC) samples of La0.7Ca0.3CoO3 (LCCO) with the perovskite structure were synthesized by conventional solid-state reaction and the floating-zone growth method. We conducted isothermal magnetization measurements of the PC and SC samples at temperatures from 2.8 K to 140 K, and evaluated the magnetic entropy change (−ΔSM) under zero field cooling (ZFC) and field cooling (FC) to 2.8 K. An interesting result has been obtained, where the −ΔSM–T curves in the low temperature range show totally different features between the ZFC and FC cooling procedures. The −ΔSM shows a large inverse irreversibility value for the ZFC …
Single-Crystal Growth And Anisotropic Magnetic Properties Of Nonstoichiometric Three-Layer Sodium Cobalt Oxides, Dapeng Chen, Xiaolin Wang, C T Lin, S X. Dou
Single-Crystal Growth And Anisotropic Magnetic Properties Of Nonstoichiometric Three-Layer Sodium Cobalt Oxides, Dapeng Chen, Xiaolin Wang, C T Lin, S X. Dou
Shi Xue Dou
Large single crystals of α-NaxCoO2 (x=0.91, 0.92, and 0.93) have been successfully fabricated by using the traveling solvent floating zone method. Details on the crystal growth are discussed. The crystal structures were characterized using powder x-ray diffraction and Rietveld refinement. The magnetic susceptibility measurements show that the magnetic properties depend strongly on x. The compound was found to be antiferromagnetic at TN ≈ 20 K for x=0.91 and x=0.92, and paramagnetic for x=0.93. The in-plane and out-of-plane anisotropies were observed for the x=0.91 crystals. In addition, the derived anisotropic g-factor ratios (gab /gc) from the anisotropic susceptibility along H||ab and …
Magnetocapacitance Effect In Nonmultiferroic Yfe03 Single Crystal, Z X. Cheng, H Shen, J Xu, Peng Liu, S J. Zhang, Jianli Wang, Xiaolin Wang, S X. Dou
Magnetocapacitance Effect In Nonmultiferroic Yfe03 Single Crystal, Z X. Cheng, H Shen, J Xu, Peng Liu, S J. Zhang, Jianli Wang, Xiaolin Wang, S X. Dou
Shi Xue Dou
YFeO3 single crystal displays two relaxor-like dielectric relaxations, one at low temperature (170300 K) and one at high temperature (370520 K), which are attributed to the activation of electrons and oxygen vacancies, respectively. Above the temperature at which electrons are activated, the sample displays a large magnetocapacitance effect. Comparison of the impedance Cole-Cole plots measured with and without applied magnetic field reveals that the occurrence of magnetocapacitance effect is accompanied with an increasing in DC conductivity under magnetic field after the activation of electrons, which is explained by the enhancement of electron jumping in Fe2b-O-Fe3b chains by magnetic field. Thus …
Very Strong Intrinsic Flux Pinning And Vortex Avalanches In (Ba, K)Fe2as2 Superconducting Single Crystals, Xiaolin Wang, Shaban R. Ghorbani, Sung-Ik Lee, S X. Dou, C T Lin, T H. Johansen, K.H Muller, Zhenxiang Cheng, Germanas Peleckis, M Shabazi, A.J Qviller, V Yurchenko, G.L Sun, D.L Sun
Very Strong Intrinsic Flux Pinning And Vortex Avalanches In (Ba, K)Fe2as2 Superconducting Single Crystals, Xiaolin Wang, Shaban R. Ghorbani, Sung-Ik Lee, S X. Dou, C T Lin, T H. Johansen, K.H Muller, Zhenxiang Cheng, Germanas Peleckis, M Shabazi, A.J Qviller, V Yurchenko, G.L Sun, D.L Sun
Shi Xue Dou
We report that the (Ba,K)Fe2As2 crystal with Tc=32 K shows a pinning potential, U0, as high as 104 K, with U0 showing very little field dependence. The (Ba,K)Fe2As2 single crystals become isotropic at low temperatures and high magnetic fields, resulting in a very rigid vortex lattice, even in fields very close to Hc2. The isotropic rigid vortices observed in the two-dimensional (2D) (Ba,K)Fe2As2 distinguish this compound from 2D high-Tc cuprate superconductors with 2D vortices. The vortex avalanches were also observed at low temperatures in the (Ba,K)Fe2As2 crystal. It is proposed that it is the K substitution that induces both almost …
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 …
Magnetic Anisotropy In Doped And Undoped Lifepo4 Single Crystals, Dapeng Chen, Xiaolin Wang, Y S Hu, C T Lin, S. X. Dou, Rashmi Nigam
Magnetic Anisotropy In Doped And Undoped Lifepo4 Single Crystals, Dapeng Chen, Xiaolin Wang, Y S Hu, C T Lin, S. X. Dou, Rashmi Nigam
Shi Xue Dou
We report on the magnetic anisotropic properties of pure and Mg doped LiFePO4 single crystals grown by the traveling solvent floating zone technique. Our results reveal a considerable anisotropy in the susceptibilities along H‖a, H‖b, and H‖c for both crystals. LiFePO4 and Li0.99Mg0.01FePO4 crystals show antiferromagnetic long-range ordering below the Néel temperature of about 52 K, with the b axis being the magnetic easy axis. The effective moments have been determined to be 6.18μB and 6.07μB for the pure and the doped crystals, respectively. These values are higher than what is expected on the basis of the spin-only value of …
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 …
Josephson-Vortex Flow Resistance In Bi2sr2ca2cu3oy Single Crystals And Its Possible Application In The Manipulation Of Spin And Charge Textures In Diluted Magnetic Semiconductors, Xiaolin Wang, C T Lin, B Liang, S Yu, S Ooi, K Hirata, S Y Ding, Dongqi Shi, S X. Dou, Zhi W. Lin, Jian G. Zhu
Josephson-Vortex Flow Resistance In Bi2sr2ca2cu3oy Single Crystals And Its Possible Application In The Manipulation Of Spin And Charge Textures In Diluted Magnetic Semiconductors, Xiaolin Wang, C T Lin, B Liang, S Yu, S Ooi, K Hirata, S Y Ding, Dongqi Shi, S X. Dou, Zhi W. Lin, Jian G. Zhu
Shi Xue Dou
In this work, the flow of the Josephson vortices (JVs) has been studied for the highly anisotropic Bi2Sr2Ca2Cu3Oy (Bi2223) single crystals. A giant flow of JVs or giant positive magnetoresistance (MR) of over 500%-2000% was obtained in fields of 0.1-5 T and remained almost constant over a wide temperature range from 110 down to 4 K, in contrast to superconducting vortices (SVs), which only produced MR in the vicinity of Tc. The flow of the JVs is expected to be much faster than that of SVs. It is proposed that the Josephson vortices could be used to manipulate the spin …
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 …
Magnetic Anisotropy Of Naxcoo2 Single Crystals, Dapeng Chen, Xiaolin Wang, C T Lin, S X. Dou
Magnetic Anisotropy Of Naxcoo2 Single Crystals, Dapeng Chen, Xiaolin Wang, C T Lin, S X. Dou
Shi Xue Dou
We report the magnetic properties of single crystals of NaxCoO2 (x=0.42, 0.82, and 0.87). The magnetic susceptibility measurements revealed considerable anisotropy along H parallel to ab and H parallel to c for the as-grown single crystals. It was found that an antiferromagnetic transition with a Neel temperature T-N=21 K occurred for the x=0.82 sample, and there was a paramagnetic phase for the x=0.87 sample over a wide temperature range from 2 to 300 K, but the sample with x=0.42 shows a monotonic increase of chi with increasing temperature above similar to 100 K. In addition, the x=0.82 sample has the …
Giant And Anisotropic Magnetoresistances In P-Type Bi-Doped Sb 2te 3 Bulk Single Crystals, Z J. Yue, Xiaolin Wang, Y Du, S M. Mahboobeh, Frank F. Yun, Z X. Cheng, S. X. Dou
Giant And Anisotropic Magnetoresistances In P-Type Bi-Doped Sb 2te 3 Bulk Single Crystals, Z J. Yue, Xiaolin Wang, Y Du, S M. Mahboobeh, Frank F. Yun, Z X. Cheng, S. X. Dou
Shi Xue Dou
Antimony telluride (Sb2Te3) compounds are well known as excellent thermoelectric materials and have been recently confirmed as three-dimensional topological insulators. In this letter, we have investigated the anisotropic magneto-transport properties of p-type Bi-doped Sb2Te3 bulk single crystals over a broad range of temperatures, degrees and magnetic fields. Giant magnetoresistance (MR) of up to 230% was observed, which exhibits quadratic field dependences in low fields and becomes linear at high fields without any trend towards saturation. The giant MR also shows strong anisotropy with anisotropy ratio up to 210% in angle-dependent measurements. The …
Dynamics Of Flux-Line Bundles And Voltage-Current Characteristics In A Ba(K)Fe2as2 Single Crystal, K H. Muller, S K. H Lam, Xiaolin Wang, S X. Dou
Dynamics Of Flux-Line Bundles And Voltage-Current Characteristics In A Ba(K)Fe2as2 Single Crystal, K H. Muller, S K. H Lam, Xiaolin Wang, S X. Dou
Shi Xue Dou
Understanding the flux-line dynamics in layered superconductors is of utmost importance for many superconductor applications, yet extracting from measurements the relevant parameters remains a major challenge. Here we report on measurements and theoretical model calculations of voltage-current (V-I) characteristics of a superconducting Ba0.72K0.28Fe2As2 single crystal slightly below its transition temperature in perpendicular magnetic fields between 0.01 and 7 T. We propose a model that describes the flux-line dynamics above, as well as below, the depinning current. The model fits the experimental V-I characteristics remarkably well and is used to extract from the data the field dependence of (a) the depinning …