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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
Jianli Wang
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 …
Domain Structures And Magnetic Anisotropy Of Tbfe12-Xtix Single Crystals, Y. Han, Z. Zhang, Jianli Wang, Guangheng Wu, X.F. Han, B.S. Han
Domain Structures And Magnetic Anisotropy Of Tbfe12-Xtix Single Crystals, Y. Han, Z. Zhang, Jianli Wang, Guangheng Wu, X.F. Han, B.S. Han
Jianli Wang
The domain structures of TbFe12-xTix (x=0.85, 1.0, and 1.3) single crystals in different crystal planes have been investigated using magnetic force microscopy. The patterns with large contrast are observed in (1 1 0) and (1 0 0) planes for the samples of x=0.85, while the slight contrast is detected in (0 0 1) plane, indicating the anisotropy is easy plane. By increasing x to 1.0 and 1.3, the domain structures change dramatically in (1 1 0), (1 0 0), and (0 0 1) planes. This demonstrates that the anisotropy transforms from easy plane to easy axis, which is related to …
Mechanosynthesis Of Nanocrystalline Mgfe2o4-Neutron Diffraction And Mossbauer Spectroscopy, V. Sepelak, I. Bergmann, A. Feldhoff, F. Litterst, K. Becker, John Cadogan, M. Hofmann, M. Hoelzel, Jianli Wang, Maxim Avdeev, Stewart Campbell
Mechanosynthesis Of Nanocrystalline Mgfe2o4-Neutron Diffraction And Mossbauer Spectroscopy, V. Sepelak, I. Bergmann, A. Feldhoff, F. Litterst, K. Becker, John Cadogan, M. Hofmann, M. Hoelzel, Jianli Wang, Maxim Avdeev, Stewart Campbell
Jianli Wang
The evolution of nanocrystalline n-MgFe2O4 by high-energy milling a mixture of MgO and α-Fe2O3 for periods of between 0 h and 12 h has been investigated by neutron diffraction in addition to previous Mössbauer, XRD and HRTEM measurements. Complete transformation of the milled products to n-MgFe2O4 only occurs on milling to ∼8 h even though the average particle size decreases to < ∼10 nm after milling for 2 h. The applied field Mössbauer spectra of n-MgFe2O4 can be well described by two subspectra representing core and shell regions with different cation distributions and spin canting angles. The neutron pattern of nanocrystalline …
Positive And Negative Exchange Bias Effects In The Simple Perovskite Manganite Ndmno3, Fang Hong, Zhenxiang Cheng, Jianli Wang, Xiaolin Wang, S X. Dou
Positive And Negative Exchange Bias Effects In The Simple Perovskite Manganite Ndmno3, Fang Hong, Zhenxiang Cheng, Jianli Wang, Xiaolin Wang, S X. Dou
Jianli Wang
Exchange bias effects were studied in the simple perovskite NdMnO 3. Nd 3+ ordering is induced by the Mn 3+ ferromagnetic component, and they are antiferromagnetically coupled with each other. At 30 K, both negative and positive exchange bias effects are found, which are dependent on the cooling field. The exchange bias fields are around -2400 Oe and 1800 Oe, respectively. Positive and negative exchange bias effects were also observed at 8 K, but the exchange bias fields are only 130 Oe and -120 Oe. The coupling intensity between Nd 3+ ordering and Mn 3+ ordering, and their initial states …
Structure And Magnetic Properties Of Rni2mn Compounds (R=Tb, Dy, Ho And Er), Jianli Wang, C. Marquina, M. R. Ibarra, Guangheng Wu
Structure And Magnetic Properties Of Rni2mn Compounds (R=Tb, Dy, Ho And Er), Jianli Wang, C. Marquina, M. R. Ibarra, Guangheng Wu
Jianli Wang
The compounds RNi2Mn (R=Tb,Dy,Ho,andEr) with a MgCu2-type structure have been synthesized. The R to transition metal atom ratio is confirmed to be 1:3 using the energy dispersive spectroscopy. The structural and magnetic properties have been investigated by various experimental methods. The x-ray diffraction patterns (XRD) can be well indexed with a cubic Laves cell and space group Fd3m. The refinement results of the XRD patterns show the presence of vacancies in the crystallographic structure. The ordering temperatures TC have been derived to be 131, 94, 75, and 50K for R=Tb,Dy,HoandEr, respectively, which are much higher than those of their corresponding …
Magnetic Structures Of Pr0.8lu0.2mn2ge2 And Pr0.6lu0.4mn2ge2, Jianli Wang, A J Studer, S.J Campbell, Shane Kennedy, Rong Zeng, S. Dou, Guangheng Wu
Magnetic Structures Of Pr0.8lu0.2mn2ge2 And Pr0.6lu0.4mn2ge2, Jianli Wang, A J Studer, S.J Campbell, Shane Kennedy, Rong Zeng, S. Dou, Guangheng Wu
Jianli Wang
The magnetic structures of Pr0.8Lu0.2Mn2Ge2 and Pr0.6Lu0.4Mn2Ge2 have been determined by neutron powder diffraction over the temperature range 10-450 K. On cooling from the paramagnetic region the Mn sublattice of Pr0.8Lu0.2Mn2Ge2 orders in a similar manner to PrMn2Ge2 with first ab-plane intralayer antiferromagnetism (AFl) below TNintra ~ 397 K followed by canted ferromagnetism (Fmc) at TCinter ~ 330 K and then a conical (Fmi) spin structure below Tc/c ~ 192 …
Abnormal Magnetic Behaviors And Large Magnetocaloric Effect In Mnps3 Nanoparticles, R Zeng, S Q. Wang, G D. Du, Jianli Wang, J C. Debnath, Precious Shamba, Z Y. Fang, S. X. Dou
Abnormal Magnetic Behaviors And Large Magnetocaloric Effect In Mnps3 Nanoparticles, R Zeng, S Q. Wang, G D. Du, Jianli Wang, J C. Debnath, Precious Shamba, Z Y. Fang, S. X. Dou
Jianli Wang
A nanostructured honeycomb lattice consisting of MnPS3 nanoparticles synthesized via the ion-exchange technique was found to have restacked molecular layers stabilized by H2O insertion between the layers. Susceptibility (χ) and heat capacity measurements showed the absence of long range magnetic ordering, at least down to 2 K. However, the χ data showed that the system possesses a high effective Curie temperature, suggesting that the system is in a high spin lattice disordered state. Evaluation of the magnetocaloric effect indicates that the system has a large reversible magnetic-entropy change (−ΔSm) of 6.8 and 12.8 J/kg K and an adiabatic temperature change …
Improvement Of Jc And Hc2 In Mgb2 Superconductor With Citric Acid Addition, Rong Zeng, Lin Lu, Jianli Wang, Wenxian Li, Dongqi Shi, Josip Horvat, S. X. Dou
Improvement Of Jc And Hc2 In Mgb2 Superconductor With Citric Acid Addition, Rong Zeng, Lin Lu, Jianli Wang, Wenxian Li, Dongqi Shi, Josip Horvat, S. X. Dou
Jianli Wang
This paper reports on the fabrication and characterization of citric acid (CA)-C6H8O7 added MgB2 superconductor. The relationships between microstructures, critical current density (Jc), critical temperature (Tc), upper critical field (Hc2), irreversibility field (Hirr), and normal state resistivity for 10 wt% C6H8O7 added MgB2 samples sintered at temperatures from 650C to 950C were systematically studied. A reduction in Tc and in lattice parameter a due to the C substitution and possible oxygen (O) effects occurs wtih C6H8O7 addition. Jc, Hc2, and Hirr are significantly enhanced, however, with the addition of C6H8O7. All the samples exhibit Jc above 104 A/cm2 at 5 …
Stress/Strain Induced Flux Pinning In Highly Dense Mgb2 Bulks, Rong Zeng, S X. Dou, Lin Lu, Wenxian Li, Chung-Kiak Poh, Jung Ho Kim, Josip Horvat, Dongqi Shi, Jianli Wang, Paul G. Munroe, X. F. Wang, Rongkun Zheng, S. P. Ringer, M Rindfleisch, Mike Tomsic
Stress/Strain Induced Flux Pinning In Highly Dense Mgb2 Bulks, Rong Zeng, S X. Dou, Lin Lu, Wenxian Li, Chung-Kiak Poh, Jung Ho Kim, Josip Horvat, Dongqi Shi, Jianli Wang, Paul G. Munroe, X. F. Wang, Rongkun Zheng, S. P. Ringer, M Rindfleisch, Mike Tomsic
Jianli Wang
We have systematically studied the flux pinning behavior of MgB2 bulks synthesized by direct diffusion of Mg into pressed pellets of high purity crystalline B powder, with and without mixing with C and SiC nanoparticles, at a reaction temperature of 850degC for 10 hrs. All of the samples showed very high purity and high density, but their microstructure and flux pinning behavior showed significant differences. It was found that the pure MgB2 agrees with the deltaTc pinning model, nano-C doped MgB2 agrees with the deltal pinning model, while the SiC+MgB2 composite agrees with the deltaepsiv pinning model (stress/strain field pinning), …
Growth Of Atomically Flat Nanofilms And Surface Superstructures Of Intrinsic Liquid Alloys, Toshiro Yamanaka, Jianli Wang, Tadaaki Nagao, Shin Yaginuma, Canhua Liu, Andrey Tupkalo, Toshio Sakurai
Growth Of Atomically Flat Nanofilms And Surface Superstructures Of Intrinsic Liquid Alloys, Toshiro Yamanaka, Jianli Wang, Tadaaki Nagao, Shin Yaginuma, Canhua Liu, Andrey Tupkalo, Toshio Sakurai
Jianli Wang
Atomically flat nanofilms were formed during growth of Ga on a Si(111) surface using an In surfactant above the melting point of Ga (and In–Ga eutectic) throughout Ga coverages of 0.17 to 5 monolayers (0.17 ≤ ΘGa ≤5). Unique superstructures such as a quasisquare-lattice (QS) structure at ΘGa=3 to 4 and a 5x5 structure at 0Ga=5 appeared as ΘGa increased. The QS structure had Ga dimer layers similar to the square lattices of an alpha-Ga(100) plane but also maintained the 1x1 structure of Si(111). As dimer layers transformed into a monoatomic layer, QS transformed into a 5x5 structure that no …
Dyni2mn—Magnetisation And Mössbauer Spectroscopy, Jianli Wang, Stewart James Campbell, Shane Joseph Kennedy, S. X. Dou, Guang Heng Wu
Dyni2mn—Magnetisation And Mössbauer Spectroscopy, Jianli Wang, Stewart James Campbell, Shane Joseph Kennedy, S. X. Dou, Guang Heng Wu
Jianli Wang
The physical properties of DyNi2Mn doped with 57Fe have been investigated by X-ray diffraction, magnetisation (10–300 K) and 57Fe Mössbauer spectroscopy measurements (5–300 K). DyNi2Mn(57Fe) crystallizes in the MgCu2-type cubic structure (Fd−3m space group). The ordering temperature is found to be TC = 99(2) K, much higher than those of DyNi2 (∼22 K) and DyMn2 (∼35 K). Analyses of isothermal M–H curves and the related Arrott plots confirm that the magnetic phase transition at TC is second order. The magnetic entropy change around TC is 4.0 J/kg K for a magnetic field change of 0 T to 5 T. The …
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
Jianli Wang
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 …
Excess Mg Addition Mgb2 /Fe Wires With Enhanced Critical Current Density, Rong Zeng, Lin Lu, Wenxian Li, Jianli Wang, Dongqi Shi, Josip Horvat, S X. Dou, M Bhatia, M D Sumption, Edward W. Collings, Jaimoo Yoo, Mike Tomsic, M Rindfleisch
Excess Mg Addition Mgb2 /Fe Wires With Enhanced Critical Current Density, Rong Zeng, Lin Lu, Wenxian Li, Jianli Wang, Dongqi Shi, Josip Horvat, S X. Dou, M Bhatia, M D Sumption, Edward W. Collings, Jaimoo Yoo, Mike Tomsic, M Rindfleisch
Jianli Wang
MgB2 /Fe wires with 10 at. % excess Mg produced by in situ powder-in-tube processing werecompared to normal stoichiometric MgB2 /Fe wires prepared by the same method. It was found thatthe critical current density Jc and the irreversibility field (Hirr) were significantly enhanced forMgB2 /Fe wires with excess Mg. The transport Jc for 10 at. % Mg excess samples sintered at 800 degrees C, measured at a field of up to 14 T, increased by a factor of 2 compared to that for the normal MgB2 wires. The best Jc results for the 10 at. % Mg excess sample were …
Enhancement Of The Refrigerant Capacity In Low Level Boron Doped La0.8gd0.2fe11.4si1.6, P Shamba, R Zeng, Jianli Wang, S J. Campbell, S X. Dou
Enhancement Of The Refrigerant Capacity In Low Level Boron Doped La0.8gd0.2fe11.4si1.6, P Shamba, R Zeng, Jianli Wang, S J. Campbell, S X. Dou
Jianli Wang
The effects of boron doping on the itinerant-electron metamagnetic (IEM) transition and the magnetocaloric effects (MCEs) in the cubic NaZn13-type La0.8Gd0.2Fe11.4Si1.6 compound have been investigated. The Curie temperature, TC, of La0.8Gd0.2Fe11.4Si1.6Bx compounds with x=0, 0.03, 0.06, 0.2 and 0.3 was found to increase from 200 K to 222 K with increase in boron doping, x. The maximum values of the isothermal magnetic entropy change, ΔSM, (derived using the Maxwell relation for a field change ΔB=0-5 T) in La0.8Gd0.2Fe11.4Si1.6Bx with x=0, 0.03, 0.06, 0.2 and 0.3 are 14.8, 16, 15, 7.5 and 6.6 J kg−1 K−1 respectively, with corresponding values of …
Magnetic Properties Of Ho2fe17-Xmnx - Influence Of Mn Substitution, Jianli Wang, Stewart J. Campbell, A J Studer, S J. Kennedy, Rong Zeng
Magnetic Properties Of Ho2fe17-Xmnx - Influence Of Mn Substitution, Jianli Wang, Stewart J. Campbell, A J Studer, S J. Kennedy, Rong Zeng
Jianli Wang
The structural and magnetic properties of Ho2Fe17−xMnx (x=0-5) have been investigated by x-ray diffraction, Mössbauer spectroscopy and DC magnetization measurements (0-5 T) over the temperature range 4.5-350 K. Similar to other ferrimagnetic R2Fe17-xMnx systems, the unit cell volume generally increases with Mn content other than for low Mn values where a slight maximum is detected around x ∼ 0.5. The nature of the magnetic phase transitions around TC is shown by Arrot plot analysis to be second order for all samples. The Curie temperature remains essentially unchanged …
A Conductive Polypyrrole-Coated, Sulfur-Carbon Nanotube Composite For Use In Lithium-Sulfur Batteries, Jianli Wang, Lin Lu, Dongqi Shi, Richard Tandiono, Zhaoxiang Wang, Konstantin Konstantinov, Hua Liu
A Conductive Polypyrrole-Coated, Sulfur-Carbon Nanotube Composite For Use In Lithium-Sulfur Batteries, Jianli Wang, Lin Lu, Dongqi Shi, Richard Tandiono, Zhaoxiang Wang, Konstantin Konstantinov, Hua Liu
Jianli Wang
A novel ternary composite, polypyrrole (PPy)-coated sulphur-carbon nanotube (S-CNT), is synthesised by using an in situ, one-pot method. Firstly, elemental sulfur is loaded into the CNT network by a solution-based processing technique. Then conducting PPy is coated on the surface of the S-CNT composite to form the S-CNT-PPy ternary composite by carrying out polymerization of the pyrrole monomer in situ. The ternary composite is tested as a cathode for lithium-sulfur batteries. The results show that PPy coating improves significantly the performance of the binary composites (S-CNT and S-PPy). The conducting PPy is believed to serve multiple functions in the composite: …
Effects Of C Substitution On The Pinning Mechanism Of Mgb2, Jianli Wang, Rong Zeng, Jung Ho Kim, Lin Lu, S. X. Dou
Effects Of C Substitution On The Pinning Mechanism Of Mgb2, Jianli Wang, Rong Zeng, Jung Ho Kim, Lin Lu, S. X. Dou
Jianli Wang
The temperature and magnetic field of the critical current density of four selected pure and C-doped MgB2 samples have been investigated in detail and the flux pinning mechanism has been analyzed. It was found that the sintering temperature and the substitution of carbon can significantly modify the flux pinning mechanism. Below 30 K, the reduced field dependences of the reduced pinning force for all investigated samples were found to closely obey one scaling law, reflecting the presence of only one dominant pinning mechanism. A delta T-c pinning mechanism was found to be mainly responsible in pure MgB2 samples while the …
Magnetocaloric Effect In Layered Ndmn2ge0.4si1.6, Jianli Wang, S.J Campbell, J.M Cadogan, A J Studer, Rong Zeng, S. X. Dou
Magnetocaloric Effect In Layered Ndmn2ge0.4si1.6, Jianli Wang, S.J Campbell, J.M Cadogan, A J Studer, Rong Zeng, S. X. Dou
Jianli Wang
A giant magnetocaloric effect has been observed in NdMn2Ge0.4Si1.6 associated with the first-order magnetic phase transition from antiferromagnetism to ferromagnetism around TC = 36 K. The magnetic entropy change –ΔSM and adiabatic temperature change ΔTad have been determined from magnetization and specific heat measurements (B = 0–5 T) with –ΔSM calculated by the Maxwell relation and Clausius–Clapeyron method. The values –ΔSMmax = 12.3 J kg−1 K−1 and refrigerant capacity ∼ 95 J/kg for ΔB = 0–2 T as derived from the Maxwell relation, together with the small hysteresis (thermal 2Ge0.4Si1.6 for refrigeration applications.
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
Jianli Wang
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 …
Phase Gap In Pseudoternary R1-Yry Mn2x 2-Xxx Compounds, Jianli Wang, S J. Kennedy, S J. Campbell, M Hofmann, S X. Dou
Phase Gap In Pseudoternary R1-Yry Mn2x 2-Xxx Compounds, Jianli Wang, S J. Kennedy, S J. Campbell, M Hofmann, S X. Dou
Jianli Wang
Our neutron diffraction investigation of PrMn2Ge2−xSix reveals a clear separation into two magnetic phases, canted ferromagnetic (Fmc) and antiferromagnetic (AFmc), between x = 1.0 and 1.2 and a commensurate phase gap in the lattice, due to magnetostrictive distortion. This remarkable magnetoelastic phenomenon is driven by a nonuniform atomic distribution on the X site which in turn produces subtle variations in the local lattice and abrupt changes in the Mn-Mn magnetic exchange interaction. Our results show that coexistence of Fmc and AFmc phases depends on lattice parameter, chemical pressure from the rare-earth and metalloid sites, and local lattice strain distributions. We …
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 …
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
Jianli Wang
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.
Sugar As An Optimal Carbon Source For The Enhanced Performance Of Mgb2 Superconductors At High Magnetic Fields, Olga Shcherbakova, Alexey Pan, Jianli Wang, Andrey Shcherbakov, S. Dou, David Wexler, E Babic, M Jercinovic, O Husnjak
Sugar As An Optimal Carbon Source For The Enhanced Performance Of Mgb2 Superconductors At High Magnetic Fields, Olga Shcherbakova, Alexey Pan, Jianli Wang, Andrey Shcherbakov, S. Dou, David Wexler, E Babic, M Jercinovic, O Husnjak
Jianli Wang
In this paper we report the results of an extended study of the effect of sugar doping on the structural and electromagnetic properties of MgB2 superconductors. High values of the upper critical field (Bc2) of 36 T and the irreversibility field (Birr) of 27 T have been estimated at the temperature of 5 K in a bulk MgB2 sample with the addition of 10 wt% of sugar. The critical current density (Jc(Ba)) of sugar-doped samples has been significantly improved in the high field region. The value of transport Jc has reached as high as 108 A m-2 at 10 T …
Magnetovolume Effect And Magnetic Properties Of Dy2fe17-Xmnx, Jianli Wang, Stewart J. Campbell, O Tegus, C Marquina, M R. Ibarra
Magnetovolume Effect And Magnetic Properties Of Dy2fe17-Xmnx, Jianli Wang, Stewart J. Campbell, O Tegus, C Marquina, M R. Ibarra
Jianli Wang
The structural and magnetic properties of Dy2Fe17−xMnx (x=0–5) compounds have been investigated using x-ray diffraction, linear thermal expansion, magnetization measurements, and 57Fe Mössbauer spectroscopy. Compared with Dy2Co17−xMnx compounds for which a linear increase of the unit-cell volume V with increasing Mn fraction is found, the compositional dependence of the lattice parameters of Dy2Fe17−xMnx first exhibits a slight maximum around x=0.5 before increasing monotonically with further increase in x; this behavior can be ascribed to a spontaneous magnetostriction as confirmed by linear-thermal-expansion measurements. The Curie temperature TC remains essentially unchanged for Mn contents up to x=1 [TC=370(4) K for x=0.0, TC=373(4) …
Magnetic Properties And Magnetocaloric Effect Of (Mn1-Xnix)3sn2(X=0-0.5) Compounds, Rong Zeng, Lin Lu, Jung Ho Kim, Dongqi Shi, Hua-Kun Liu, S. X. Dou, Jianli Wang, Stewart J. Campbell, Zhaoxiang Wang, Y Li, Wenxian Li, M Y. Zhu, Chuanqi Feng
Magnetic Properties And Magnetocaloric Effect Of (Mn1-Xnix)3sn2(X=0-0.5) Compounds, Rong Zeng, Lin Lu, Jung Ho Kim, Dongqi Shi, Hua-Kun Liu, S. X. Dou, Jianli Wang, Stewart J. Campbell, Zhaoxiang Wang, Y Li, Wenxian Li, M Y. Zhu, Chuanqi Feng
Jianli Wang
The effects of Ni substitution on the magnetic properties and magnetocaloric effect (MCE) of (Mn1−xNix)3Sn2 compounds (x = 0–0.5) have been investigated by x-ray diffraction and magnetization measurements. It was found that Ni substitution decreases the crystal cell volume and the magnetic transition temperatures compared with pure Mn3Sn2. The MCE for all samples has been calculated from the magnetization data in terms of the isothermal magnetic entropy change ΔSM. The maximum values of ΔSMmax at the magnetic phase transition temperatures resulting from a change in magnetic field of ΔH = 5 T were found to be 28.2 mJ/cm3 K for …
Substitution Of Y For Pr In Prmn2ge2-The Magnetism Of Pr0.8y0.2mn2ge2, Jianli Wang, S Campbell, M Hofmann, S Kennedy, M Avdeev, M Md Din, R Zeng, Z Cheng, S Dou
Substitution Of Y For Pr In Prmn2ge2-The Magnetism Of Pr0.8y0.2mn2ge2, Jianli Wang, S Campbell, M Hofmann, S Kennedy, M Avdeev, M Md Din, R Zeng, Z Cheng, S Dou
Jianli Wang
Pr0.8Y0.2Mn2 Ge 2 is found to exhibit four magnetic transitions on decreasing the temperature from the paramagnetic region: (i) paramagnetism to intralayer antiferromagnetism (AFl) at TN intra; (ii) AFl to canted ferromagnetism (Fmc) at TC inter; (iii) Fmc to conical magnetic ordering of the Mn sublattice (Fmi) at Tcc; and (iv) Fmi(Mn) to Fmi(Mn) + F(Pr) at TC Pr. These changes in magnetic structure are discussed in terms of changes in the Mn-Mn separation distances caused by the unit cell contraction and by electronic effects due to replacement of 20% of Pr with Y.
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
Jianli Wang
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, …
Significant Improvement In The Critical Current Density Of In Situ Mgb2 By Excess Mg Addition, R Zeng, L Lu, Jianli Wang, J Horvat, W Li, Dongqi Shi, S Dou, M Tomsic, M Rindfleisch
Significant Improvement In The Critical Current Density Of In Situ Mgb2 By Excess Mg Addition, R Zeng, L Lu, Jianli Wang, J Horvat, W Li, Dongqi Shi, S Dou, M Tomsic, M Rindfleisch
Jianli Wang
We present a detailed analysis of the effects of excess Mg on the lattice parameters, the critical temperature (Tc), the critical current (Jc), the irreversibility field (Hirr), and the upper critical field (Hc2) of MgB2 bulks and wires produced by an in situ solid-state reaction method and the powder-in-tube method, respectively. It was found that Jc, Hirr, and Hc2 were significantly enhanced for Mg excess samples. All these properties were highly sensitive to the processing temperature for Mg excess samples, while there was only a weak dependence on processing temperature for normal ones. The Tc variation for the 10% Mg …
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
Jianli Wang
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 …
Three First Order Magnetic Phase Transitions In Re-Entrant Ferromagnet Prmn1.4fe0.6ge2, Rong Zeng, Jianli Wang, Lin Lu, Wenxian Li, Stewart Campbell, S Dou
Three First Order Magnetic Phase Transitions In Re-Entrant Ferromagnet Prmn1.4fe0.6ge2, Rong Zeng, Jianli Wang, Lin Lu, Wenxian Li, Stewart Campbell, S Dou
Jianli Wang
Three first order magnetic phase transitions (FOMTs) have been detected and evaluated over the temperature range from 5 to 340 K at fields up to 9 T in PrMn1.4Fe0.6Ge2. All three FOMTs, from (with decreasing temperature) an antiferromagnetic (AFl) to a c-axis canted ferromagnetic (Fmc) state, to a c-axis canted antiferromagnetic (AFmc) state, and then to an Fmc state plus an additional Pr-sublattice magnetic contribution (Fmc + F(Pr)), exhibited temperature and field-induced transition features. A interesting phenomenon was observed, in that magnetic field can induce an AFmc to Fmc + F(Pr) transition, and then diminish and finally eliminate the re-entrant …