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Magnetic Properties Of Bi2femno6: A Multiferroic Material With Double-Perovskite Structure, Yi Du, Zhenxiang Cheng, S X. Dou, Xiaolin Wang, Hua Zhao, Hideo Kimura
Magnetic Properties Of Bi2femno6: A Multiferroic Material With Double-Perovskite Structure, Yi Du, Zhenxiang Cheng, S X. Dou, Xiaolin Wang, Hua Zhao, Hideo Kimura
Shi Xue Dou
Single phase Bi2FeMnO6 was synthesized on Si substrates by an electrospray method. Three peaks were observed in the temperature dependence of magnetization curve, which is attributed to the inhomogeneous distribution of Fe3+ and Mn3+. The observed magnetic peaks at 150 K, 260 K, and 440 K correspond to orderings of the ferrimagnetic Fe–O–Mn, and antiferromagnetic Mn–O–Mn and Fe–O–Fe, respectively. Heat capacity measurements were carried out to confirm these magnetic transitions. The Debye temperature of Bi2FeMnO6 is 339 K, calculated from Debye–Einstein fitting.
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
Shi Xue Dou
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 a magnetic field change of 0 to 5 T with its relative cooling power …
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 …
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
Shi Xue Dou
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 the magnetic and exchange …
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga V. Shcherbakova, Alexey V. Pan, Jianli Wang, Andrey Shcherbakov, S. X. Dou, David Wexler
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga V. Shcherbakova, Alexey V. Pan, Jianli Wang, Andrey Shcherbakov, S. X. Dou, David Wexler
Shi Xue Dou
Structural analysis and electromagnetic measurements have been performed on a range of samples prepared by the liquid mixing approach to doping MgB2 are sugar, malic acid, and polycarbosilane. The results obtained have allowed us to clarify the contributions of the factors limiting critical current at low magnetic fields in doped MgB2.
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.
Peak Effect In The Critical Current Of Type Ii Superconductors With Strong Magnetic Vortex Pinning, X B. Xu, H Fangohr, X N. Xu, M Gu, Z H Wang, S M. Ji, Shichao Ding, Dongqi Shi, S. X. Dou
Peak Effect In The Critical Current Of Type Ii Superconductors With Strong Magnetic Vortex Pinning, X B. Xu, H Fangohr, X N. Xu, M Gu, Z H Wang, S M. Ji, Shichao Ding, Dongqi Shi, S. X. Dou
Shi Xue Dou
We perform 2D Langevin simulations studying the peak effect (PE) of the critical current taking into account the temperature dependence of the competing forces. We observe and report that the PE results from the competition of vortex-vortex interactions and vortex-pin interactions which have different temperature dependencies. The simulations reveal that the PE can take place only for certain pinning strengths, densities of pinning centres, and driving forces, which is in good agreement with experiments. No apparent vortex order-disorder transition is observed across the PE regime. In addition, the PE is a dynamical phenomenon, and thermal fluctuations can speed up the …
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
Shi Xue Dou
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 particles exhibits a lower …
Magnetic Phase Transitions In Pr1-Xluxmn2ge2 Compounds, S X. Dou, Jianli Wang, Maxim Avdeev, A J Studer, Rong Zeng, Stewart J. Campbell
Magnetic Phase Transitions In Pr1-Xluxmn2ge2 Compounds, S X. Dou, Jianli Wang, Maxim Avdeev, A J Studer, Rong Zeng, Stewart J. Campbell
Shi Xue Dou
The effects of replacing Pr by Lu on the magnetic behaviour and structures of Pr1−xLuxMn2Ge2 (x = 0.2,x = 0.4) have been investigated using x-ray diffraction, Mössbauer spectroscopy, magnetization and neutron diffraction measurements. The substitution of Lu for Pr leads to a decrease in the lattice constants a, c and the unit cell volume V at room temperature with this contraction of the unit cell resulting in modifications of the Pr1−xLuxMn2Ge2 magnetic structures. Four and five magnetic phase transitions—linked primarily with temperature driven changes in the intralayer Mn–Mn separation distances—have been detected within the temperature range 4.5–550 K for Pr0.8Lu0.2Mn2Ge2 …
Magnetic Structures And Phase Transitions In Prmn2-Xfexge2, Jianli Wang, Stewart J. Campbell, A J Studer, Maxim Avdeev, M Hofmann, M Hoelzel, S. X. Dou
Magnetic Structures And Phase Transitions In Prmn2-Xfexge2, Jianli Wang, Stewart J. Campbell, A J Studer, Maxim Avdeev, M Hofmann, M Hoelzel, S. X. Dou
Shi Xue Dou
The magnetic properties and magnetic structures of PrMn2-xFexGe2 compounds (space group I4/mmm) have been investigated using magnetic, 57Fe Mössbauer effect (x=1.0, 1.3, 1.6) and neutron diffraction measurements (x=0.4, 0.6, 0.8, 1.3) over the temperature range 3-410 K. This has enabled the existing magnetic phase diagram for PrMn2-xFexGe2 to be extended from Fe concentration, x=0-1, to the full range x = 0-2 in terms of concentration and dMn-Mn, the intralayer distance.
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, …
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
Shi Xue Dou
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 of the Mn sublattice Fmi at Tcc ~ 178 K and (iv) Fmi(Mn) to Fmi(Mn)+F(Nd) at TNdC ~ 72 K.
Magnetic And Superconducting Properties Of Spin-Fluctuation-Limited Superconducting Nanoscale Vnx, R Zeng, J Liu, G Du, W. X. Li, J Wang, J Horvat, S X. Dou
Magnetic And Superconducting Properties Of Spin-Fluctuation-Limited Superconducting Nanoscale Vnx, R Zeng, J Liu, G Du, W. X. Li, J Wang, J Horvat, S X. Dou
Shi Xue Dou
"VNx nanoparticles and nanowires have been prepared by nitrifying V2O5 nanoparticles (NP) and nanowires (NW). The V2O5 NP and NW were synthesized by a facile hydrothermal method. Magnetic susceptibility (chi) and magnetization measurements showed long range superconducting ordering (LRSO) at the temperature of 5.8 K for NW, but there was no observation of LRSO (at least down to 2 K) for the NP sample, which is a much lower temperature than for the corresponding bulk, while both NP and NW showed the absence of long range magnetic ordering, at least down to 2 K. However, the chi data showed that …
Magnetic Phase Transition In Mnfep0.5as0.4si 0.1, Jianli Wang, Stewart J. Campbell, O Tegus, E Bruck, S X. Dou
Magnetic Phase Transition In Mnfep0.5as0.4si 0.1, Jianli Wang, Stewart J. Campbell, O Tegus, E Bruck, S X. Dou
Shi Xue Dou
We have carried out a detailed investigation of the magnetic phase transition in MnFeP0.5As0.4Si0.1. Temperature hysteresis has been observed in the variable temperature magnetization curves (Bappl = 0.01 T) with TC W ~ 302 K on warming and TC C ~ 292 K on cooling. The first order nature of this transition in MnFeP0.5As0.4Si0.1 is confirmed by the negative slope obtained from isotherms of M2 versus B/M around the critical temperature. Linear thermal expansion measurements reveal a large volume change, ΔV/V∼8.7×10-3, at the magnetic phase transition and that this magnetovolume effect is suppressed to ΔV/V ∼ 5.5×10-3 in an applied …
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.
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 …
"Density Of States, Magnetic And Transport Properties Of Nd Doped Two Dimensional Perovskite Compound Sr2coo4", Qiwen Yao, Hideo Kimura, Xiaolin Wang, Kosta Konstantinov, Hongyang Zhao, Hai Qiu, Rumi Tanahashi, Kiyoshi Ozawa, S. X. Dou
"Density Of States, Magnetic And Transport Properties Of Nd Doped Two Dimensional Perovskite Compound Sr2coo4", Qiwen Yao, Hideo Kimura, Xiaolin Wang, Kosta Konstantinov, Hongyang Zhao, Hai Qiu, Rumi Tanahashi, Kiyoshi Ozawa, S. X. Dou
Shi Xue Dou
"Structures, transport, magnetic properties, and first principle calculation results will be reported for the two dimensional layered structured perovskite compounds Sr2-xNdxCoO4 (x = 0.5, 0.75, 1, 1.25). Structure refinement results revealed that these compounds crystallized in K2NiF4-type structures with space group I4/mmm. The temperature dependence of resistivity showed semiconductor like behavior for these samples. It was found that the lattice parameter c decreases as the doping level x increases. The compounds exhibited a paramagnetic to ferromagnetic transition at temperatures of about 170, 125 K for the x = 1 and 0.75 samples, respectively. The temperature dependence of resistivity for the …
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
Shi Xue Dou
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 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 …
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
Shi Xue Dou
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 flux pinning emerges at high temperatures, and it is believed to arise from the special magnetic …
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 …
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.
Structure, Magnetic, And Thermal Properties Of Nd1-Xlaxcro3 (0 ≤ X ≤ 1.0), Yi Du, Zhenxiang Cheng, Xiaolin Wang, S X. Dou
Structure, Magnetic, And Thermal Properties Of Nd1-Xlaxcro3 (0 ≤ X ≤ 1.0), Yi Du, Zhenxiang Cheng, Xiaolin Wang, S X. Dou
Shi Xue Dou
Perovskite-type Nd1−xLaxCrO3(0 ≤ x ≤1.0) polycrystalline samples were synthesized using solid state reaction. Structural studies indicate that the lattice parameters, metal–oxygen bond lengths, and angles of Nd1−xLaxCrO3 strongly depend on the La content. Two magnetic transition temperatures, Cr3+ antiferromagnetic ordering temperature (TN) and the spin reorientation phase transition temperature (TSRPT), have been observed in the M-T curves. The increase in TN and decrease in TSRPT with increasing x value can be explained by the change in the magnetic interactions due to La doping. The heat capacity of Nd1−xLaxCrO3 measured from 2 to 300 K reveals that the lattice, electronic, and …
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
Shi Xue Dou
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 its own magnetic behaviour which is similar yet distinct from the main …
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 …
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 …
Kinetic Roughening Of Magnetic Flux Penetration In Mgb2 Thin Films, Andrea Lucarelli, Stephanie Hummert, Andrea Chaney, Gunter Lupke, Brian Moeckly, Yue Zhao, S X. Dou
Kinetic Roughening Of Magnetic Flux Penetration In Mgb2 Thin Films, Andrea Lucarelli, Stephanie Hummert, Andrea Chaney, Gunter Lupke, Brian Moeckly, Yue Zhao, S X. Dou
Shi Xue Dou
Time-resolved magneto-optical studies are performed on MgB2 thin film samples grown by in situ pulsed laser deposition and in situ reactive deposition technique. The latter reveal dendritic avalanche-free flux penetration. The kinetic roughening of magnetic flux penetration is studied for applied ac current. Dynamic scaling laws determined for both static field and ac current are consistent with the directed percolation depinning model, placing the vortex dynamics in MgB2 in the same universality class as YBCO and Nb.
Magnetic Glassy Behaviour In Ferroelectric Relaxor Type Solid Solutions: Magnetelectric Relaxor, Zhenxiang Cheng, Xiaolin Wang, Gustavo A. Alvarez, S. X. Dou, Shujun Zhang, Thomas R. Shrout
Magnetic Glassy Behaviour In Ferroelectric Relaxor Type Solid Solutions: Magnetelectric Relaxor, Zhenxiang Cheng, Xiaolin Wang, Gustavo A. Alvarez, S. X. Dou, Shujun Zhang, Thomas R. Shrout
Shi Xue Dou
Perovskite solid solution ceramics with compositions of 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3, 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3, and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 were synthesized by the traditional solid state reaction method. Ferroelectric measurements revealed that these samples have well saturated polarization-electrical field loops. Dielectric measurements showed that abnormal dielectric peaks at their Curie temperature were frequency dependent. Both characteristics indicate that these samples are relaxor type ferroelectric materials. Field cooled and zero field cooled magnetization measurements revealed that the 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3 and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 samples are paramagnetic down to 5 K, while the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 sample shows an antiferromagnetic-like ordering starting from around 40 K. Furthermore, a weak ferromagnetism is observed in the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 …
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 …