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Full-Text Articles in Engineering
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
Faculty of Engineering - Papers (Archive)
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 …
Critical Magnetic Transition In Tbni2mn-Magnetization And Mossbauer Spectroscopy, Jianli Wang, S J. Campbell, S J. Kennedy, Rong Zeng, S. X. Dou, Guangheng Wu
Critical Magnetic Transition In Tbni2mn-Magnetization And Mossbauer Spectroscopy, Jianli Wang, S J. Campbell, S J. Kennedy, Rong Zeng, S. X. Dou, Guangheng Wu
Faculty of Engineering - Papers (Archive)
The structural and magnetic properties of the TbNi2Mnx series (0.9 ≤ x ≤ 1.10) have been investigated using x-ray diffraction, field- and temperature-dependent ac magnetic susceptibility,DC magnetization (5-340 K; 0-5 T) and 57Fe Mössbauer spectroscopy (5-300 K). TbNi2Mnx crystallize in the MgCu2-type structure (space group Fd-3m). The additional contributions to the magnetic energy terms from transition metal-transition metal interactions (T-T) and rare earthtransition metal interactions (R-T) in RNi2Mn contribute to their increased magnetic ordering temperatures compared with RNi2 and RMn2. Both the lattice constant a and the Curie temperature TC exhibit maximal values at the x=1 composition indicating strong magnetostructural …
Robust High-Temperature Magnetic Pinning Induced By Proximity In Yba2cu3o7-8/La0.67sr0.33mno3 Hybrids, C.Z Chen, Z Y. Liu, Y M. Lu, L Zeng, C B. Cai, Rong Zeng, S. X. Dou
Robust High-Temperature Magnetic Pinning Induced By Proximity In Yba2cu3o7-8/La0.67sr0.33mno3 Hybrids, C.Z Chen, Z Y. Liu, Y M. Lu, L Zeng, C B. Cai, Rong Zeng, S. X. Dou
Faculty of Engineering - Papers (Archive)
An elaborately designed bilayer consisting of superconducting YBa2Cu3O7-6 (YBCO) and ferromagnetic La0.67Sr0.33MnO3-6 (LSMO) was prepared on a single crystal LaAlO3 substrate by pulsed laser deposition (PLD), with a view to understanding the mechanism behind the influence of superconductor/ferromagnet proximity on the critical current density, Jc. The present bilayer system shows significant modifications in Jc, as evidenced by the suppressed decay of its temperature dependence, as well as the crossing behavior of the magnetic field dependence of Jc at high temperatures. This indicates that enhanced …
Fabrication, Magnetic, And Ferroelectric Properties Of Multiferroic Bifeo3 Hollow Nanoparticles, Yi Du, Zhenxiang Cheng, S X. Dou, Darren J. Attard, Xiaolin Wang
Fabrication, Magnetic, And Ferroelectric Properties Of Multiferroic Bifeo3 Hollow Nanoparticles, Yi Du, Zhenxiang Cheng, S X. Dou, Darren J. Attard, Xiaolin Wang
Faculty of Engineering - Papers (Archive)
Hollow BiFeO3 nanoparticles were synthesized by an electrospray route for the first time. The phase purity and structure have been investigated by x-ray diffraction and Raman spectroscopy. Transmission and scanning electron microscope investigations revealed that the as-obtained BiFeO3 hollow spheres were polycrystalline, with a shell thickness of 35 nm. The formation mechanism can be possibly explained by Ostwald ripening. Raman spectra have verified decreased vibrational frequencies in BiFeO3 nanoparticles. These hollow and core-shell multiferroic nanoparticles exhibit significantly enhanced ferromagnetism from 5 to 600 K due to a broken spiral spin structure. The ferroelectricity of hollow BiFeO3 …
Magnetoresistance, Critical Current Density, And Magnetic Flux Pinning Mechanism In Nickel Doped Bafe2as2 Single Crystals, Mahboobeh Shahbazi, Xiaolin Wang, Z W. Lin, J G. Zhu, S. X. Dou, K Y. Choi
Magnetoresistance, Critical Current Density, And Magnetic Flux Pinning Mechanism In Nickel Doped Bafe2as2 Single Crystals, Mahboobeh Shahbazi, Xiaolin Wang, Z W. Lin, J G. Zhu, S. X. Dou, K Y. Choi
Faculty of Engineering - Papers (Archive)
The critical current density, Jc, flux pinning behavior and magneto- resistance results of BaFe2-xNixAs2 single crystal have been investigated in fields up to 13 T over a temperature range of 2 to 20 K. The magnetoresistance below the superconducting transition temperature (Tc) shows Arrhenius thermally activated behavior: ρ = ρoexp(-Uo(T,H)/kBT), where Uo is the thermally activated energy. BaFe2-xNixAs2 exhibits high thermally activated flux flow energy with a very weak …
Reduction Of Hysteresis Losses In The Magnetic Refrigerant La0.8ce0.2fe11.4si1.6 By The Addition Of Boron, Precious Shamba, J.C Debnath, Rong Zeng, Jianli Wang, Stewart J. Campbell, S J. Kennedy, S. X. Dou
Reduction Of Hysteresis Losses In The Magnetic Refrigerant La0.8ce0.2fe11.4si1.6 By The Addition Of Boron, Precious Shamba, J.C Debnath, Rong Zeng, Jianli Wang, Stewart J. Campbell, S J. Kennedy, S. X. Dou
Faculty of Engineering - Papers (Archive)
In an effort to improve the magnetocaloric effects of the NaZn13-type La0.8Ce0.2Fe11.4Si1.6 compound, the effect of boron doping on the magnetic properties and magnetocaloric properties has been investigated. The magnetic entropy change (ΔSM) for the La0.8Ce0.2Fe11.4Si1.6 compound, obtained for a field change of 0–5 T using the Maxwell relation exhibits a spike and appears to be overestimated and is thus corrected by using the Clausius-Clapeyron equation (CC). The ΔSM determined from the CC equation is estimated to be 19.6 J kg …
Magnetic And Ferroelectric Properties Of Multiferroic Bi2nimno6 Nanoparticles, Yi Du, Zhenxiang Cheng, Xiaolin Wang, Peng Liu, S. X. Dou
Magnetic And Ferroelectric Properties Of Multiferroic Bi2nimno6 Nanoparticles, Yi Du, Zhenxiang Cheng, Xiaolin Wang, Peng Liu, S. X. Dou
Faculty of Engineering - Papers (Archive)
Multiferroic Bi2NiMnO6 nanoparticles were synthesized by a simple electrospray method. Bi2NiMnO6 nanoparticles crystallize in the monoclinic structure with space group C121. The particles show a uniform spherical shape with a diameter of 100 nm to 300 nm. The ferromagnetic transition of Bi2NiMnO6 is confirmed at 122 K. The room temperature ferroelectricity of the Bi2NiMnO6 nanoparticles is verified by Kelvin probe force microscopy.
Strong 4f Electron Interaction And Magnetic Ordering Modification In Nd1-Xerxmno3 (0 Less Than Or Equal To X Less Than Or Equal To 0.5), Fang Hong, Zhenxiang Cheng, Xiaolin Wang
Strong 4f Electron Interaction And Magnetic Ordering Modification In Nd1-Xerxmno3 (0 Less Than Or Equal To X Less Than Or Equal To 0.5), Fang Hong, Zhenxiang Cheng, Xiaolin Wang
Faculty of Engineering - Papers (Archive)
Structural and magnetic properties have been studied in perovskite Nd1-xErxMnO3 (0 ≤ x ≤ 0.5). Er3+ doping enhances the Jahn-Teller distortion, strongly affects the Nd3+-Mn3+ interaction, destroys the intermediate state below the antiferromagnetic transition temperature in NdMnO3, and breaks the antiparallel arrangement between Nd3+ and Mn3+ spin ordering. The decreasing ferromagnetic component in magnetic hysteresis loops at 30 K indicates that the canted angles vary with x. These results offer strong evidence for the interaction between rare earth ions and transition metal ions and competition among rare …
Continuously Tunable Magnetic Phase Transitions In The Dymn1-Xfexo3 System, Fang Hong, Zhenxiang Cheng, Hongyang Zhao, Hideo Kimura, Xiaolin Wang
Continuously Tunable Magnetic Phase Transitions In The Dymn1-Xfexo3 System, Fang Hong, Zhenxiang Cheng, Hongyang Zhao, Hideo Kimura, Xiaolin Wang
Faculty of Engineering - Papers (Archive)
The structure and magnetic properties of perovskite DyMn1−xFexO3 samples have been studied. Static orbital orderings are expected to exist in samples with x ≤ 0.2 due to strong Jahn-Teller distortion, which become less stable as x increases and probably disappears in samples with x > 0.5. The antiferromagnetic transition temperature increases as x increases. At the composition x > 0.5, spin reorientation starts to appear. Meanwhile, the spin reorientation temperature and the antiferromagnetic Néel temperature gradually separate and widen the temperature range of the magnetic metastable state between these two transitions. The magnetic competition is discussed based …
Giant Magnetic Flux Jumps In Single Crystals Of Ba0.6k0.4fe2as2, Ki-Young Choi, Gun Sang Jeon, X.F Wang, X.H Chen, Xiaolin Wang, Myung-Hwa Jung, Sung-Ik Lee, Gangseo Park
Giant Magnetic Flux Jumps In Single Crystals Of Ba0.6k0.4fe2as2, Ki-Young Choi, Gun Sang Jeon, X.F Wang, X.H Chen, Xiaolin Wang, Myung-Hwa Jung, Sung-Ik Lee, Gangseo Park
Faculty of Engineering - Papers (Archive)
Giant magnetic flux jumps are observed in magnetic hysteresis loops of Ba0.6K0.4Fe2As2 single crystals. The size of the flux jumps, which appear only at low temperatures (T<4 >K), is so large that it can transform the whole superconducting state into the normal state. The recovery rate to the superconducting state is rather slow, although the superconducting state is almost fully recovered. We show that theoretical predictions based on the adiabatic approach with nonlocal electrodynamics give a good explanation of the flux jumps observed in the single crystals of Ba0.6K0.4 …
Neutron Diffraction Study Of The Magnetic Order In Ndmn2ge1.6si0.4, Jianli Wang, Stewart J. Campbell, John M. Cadogan, A J Studer, Rong Zeng, S. X. Dou
Neutron Diffraction Study Of The Magnetic Order In Ndmn2ge1.6si0.4, Jianli Wang, Stewart J. Campbell, John M. Cadogan, A J Studer, Rong Zeng, S. X. Dou
Faculty of Engineering - Papers (Archive)
Here we report a detailed investigation of NdMn2Ge1.6Si0.4; this forms part of our investigation of the magnetic order across the NdMn2Ge2−xSix (x = 0–2.0) series by magnetometry, x-ray diffraction and neutron diffraction over the temperature range 6–465 K. On decreasing the temperature from 465 K, NdMn2Ge1.6Si0.4 exhibits four magnetic transitions: (i) from paramagnetism to intralayer antiferromagnetism AFl at TIntraN ~ 430 K; (ii) AFl to canted ferromagnetism Fmc at TInterC ~ 330 K; (iii) Fmc to conical magnetic ordering …
Fiber Metamaterials With Negative Magnetic Permeability In The Terahertz, Anna Wang, Alessandro Tuniz, Peter Hunt, Elise Pogson, R A. Lewis, Avi Bendavid, Simon Fleming, Boris Kuhlmey, Maryanne Large
Fiber Metamaterials With Negative Magnetic Permeability In The Terahertz, Anna Wang, Alessandro Tuniz, Peter Hunt, Elise Pogson, R A. Lewis, Avi Bendavid, Simon Fleming, Boris Kuhlmey, Maryanne Large
Faculty of Engineering - Papers (Archive)
We present a novel method for producing metamaterials with a terahertz magnetic response via fiber drawing, which can be inexpensively scaled up to mass production. We draw a centimeter preform to fiber, spool it, and partially sputter it with metal to produce extended slotted resonators. We characterize metamaterial fiber arrays with different orientations via terahertz time domain spectroscopy, observing distinct magnetic resonances between 0.3 and 0.4 THz, in excellent agreement with simulations. Numerical parameters retrieval techniques confirm that such metamaterials possess negative magnetic permeability. Combined with fiber-based negative permittivity materials, this will enable the development of the first woven negative …
The Effects Of Size And Orientation On Magnetic Properties And Exchange Bias In Co3o4 Mesoporous Nanowires, Rong Zeng, J Q Wang, Zhixin Chen, Wenxian Li, S. X. Dou
The Effects Of Size And Orientation On Magnetic Properties And Exchange Bias In Co3o4 Mesoporous Nanowires, Rong Zeng, J Q Wang, Zhixin Chen, Wenxian Li, S. X. Dou
Faculty of Engineering - Papers (Archive)
Co3O4 mesoporous nanowires with average single crystalline grain sizes of about 8 nm, 12nm, 25 nm, and 45 nm were synthesized by sintering of microwave-assisted hydrothermal processed belt-Co(OH)2 precursors at 300–500 °C for 2 h. Microstructure analysis was conducted by x-ray diffraction, x-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), field emission SEM (FESEM), transmission electron microscopy (TEM), and high resolution TEM (HRTEM) to confirm the composition, structure, and orientation in the nanowires. Systematic magnetic measurements have also been conducted on the nanowires. It was found that the size and orientation have significant effects on …
Effects Of Cu And Fe Doping On Raman Spectra And On The Structural And Magnetic Properties Of Ermno3, Peng Liu, Zhenxiang Cheng, Yi Du, Xiaolin Wang
Effects Of Cu And Fe Doping On Raman Spectra And On The Structural And Magnetic Properties Of Ermno3, Peng Liu, Zhenxiang Cheng, Yi Du, Xiaolin Wang
Faculty of Engineering - Papers (Archive)
Single phase ErMexMn1−xO3 (Me = Cu, Fe; 0 ≤ x ≤ 0.1) samples were synthesized by the solid state reaction method. The differences between the doping effects on the Raman spectra and on the structural, magnetic, and thermal properties of the two systems have been systematically investigated. In the ErCuxMn1−xO3 system, lattice parameter a increases with doping, while lattice parameter c decreases. It is more complicated in the ErFexMn1−xO3 system, where lattice parameter a decreases with doping, while lattice parameter c is enhanced after an …
Magnetic Phase Transition And Mossbauer Spectroscopy Of Erni2mnx Compounds, Jianli Wang, S J. Campbell, R Zeng, S. X. Dou, S J. Kennedy
Magnetic Phase Transition And Mossbauer Spectroscopy Of Erni2mnx Compounds, Jianli Wang, S J. Campbell, R Zeng, S. X. Dou, S J. Kennedy
Faculty of Engineering - Papers (Archive)
Investigation of ErNi2Mnx with 0.90 ≤ x ≤ 1.10 indicates that the MgCu2-type structure (with space group Fd-3m) is formed within x = 0.97−1.10. Curie temperature TC = 50 K of ErNi2Mn is significantly higher than those of the corresponding ErNi2 (TC = 7 K) and ErMn2 (TC = 15 K) compounds. Detailed analyses of DC magnetization data demonstrate that the magnetic phase transition at the Curie temperature is second order. The magnetic entropy change around TC has been found to be 4.8 J/kg K for …