Determination of the magnetic structure and confirmation of the presence or absence of inversion(P)and time reversal(Τ)symmetry is imperative for correctly understanding the topological magnetic materials.Here highqu...Determination of the magnetic structure and confirmation of the presence or absence of inversion(P)and time reversal(Τ)symmetry is imperative for correctly understanding the topological magnetic materials.Here highquality single crystals of the layered manganese pnictide CaMnSb_(2)are synthesized using the self-flux method.展开更多
The thermally assisted resonant tunnelling in a single crystal (Mno.96Cro.04)12-ac is studied in this paper. The obtained hysteresis loops at seven different temperatures between 1.8 and 3K show obvious dependence on ...The thermally assisted resonant tunnelling in a single crystal (Mno.96Cro.04)12-ac is studied in this paper. The obtained hysteresis loops at seven different temperatures between 1.8 and 3K show obvious dependence on temperature.The magnetization steps occur at specific field values of nHR with HR≈0.46T, which are approximately independent of the temperature. As the temperature decreases, the area enclosed in the hysteresis loops and the actual number n of the resonances increase, which provides clear evidence of thermally assisted resonant tunnelling in (Mn0.96Cr0.04)12-ac.展开更多
Hydrogenation, crystal structure and magnetic properties of La(Fe0.91Si0.09)13H(D)y have been studied by pressure-composition isotherms (PCI), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and magne...Hydrogenation, crystal structure and magnetic properties of La(Fe0.91Si0.09)13H(D)y have been studied by pressure-composition isotherms (PCI), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and magnetization measurements. The maximum absorption capacity is found to be 1.9 H(D) atoms per formula unit as a solid solution. All hydrides and deuterides crystallize in the NaZn13-type cubic structure with the lattice parameter increasing linearly with H(D) concentration. The H(D) absorption enhances the Curie temperature significantly. The magnetic entropy change of the highly H-absorbed compound La(Fe0.91Si0.09)13H1.81 reaches ～26 J/kg·K under a magnetic field change of 5 T near the Curie temperature TC = 350 K. No observable isotope effect seems to imply that only the magnetovolume effect is responsible for the strong interplay between magnetism and lattice.展开更多
During the past decades,Li-ion batteries have been one of the most important energy storage devices.Large-scale energy storage requires Li-ion batteries which possess high energy density,low cost,and high safety.Other...During the past decades,Li-ion batteries have been one of the most important energy storage devices.Large-scale energy storage requires Li-ion batteries which possess high energy density,low cost,and high safety.Other than advanced battery materials,in-depth understanding of the intrinsic mechanism correlated with cell reaction is also essential for the development of high-performance Li-ion battery.Advanced characterization techniques,especially neutron-based techniques,have greatly promoted Li-ion battery researches.In this review,the characteristics or capabilities of various neutron-based characterization techniques,including elastic neutron scattering,quasi-elastic neutron scattering,neutron imaging,and inelastic neutron scattering,for the related Li-ion-battery researches are summarized.The design of in-situ/operando environment is also discussed.The comprehensive survey on neutron-based characterizations for mechanism understanding will provide guidance for the further study of high-performance Li-ion batteries.展开更多
In this paper, multiferroics and magnetocapacitive effect of triangular-lattice antiferromagnet Ag Al0.02Cr0.98S2 are investigated by magnetic, ferroelectric, pyroelectric current and dielectric measurement. We find t...In this paper, multiferroics and magnetocapacitive effect of triangular-lattice antiferromagnet Ag Al0.02Cr0.98S2 are investigated by magnetic, ferroelectric, pyroelectric current and dielectric measurement. We find that it is a multiferroic material and the magnetocapacitive effect reaches a factor of up to 90 in an external field of 7 T. The results imply the further possibility of synthesizing the magnetocapacitive materials by modifying the frustrated spin structure in terms of a few B-site doping nonmagnetic ions.展开更多
In this paper,magnetic and dielectric properties of the quasi-two-dimensional triangular-lattice system CuCrS2 and its B-site-diluted analogs CuAl1?xCrxS2(x = 0.01 and x = 0.02) are investigated.Antiferromagnetic phas...In this paper,magnetic and dielectric properties of the quasi-two-dimensional triangular-lattice system CuCrS2 and its B-site-diluted analogs CuAl1?xCrxS2(x = 0.01 and x = 0.02) are investigated.Antiferromagnetic phase transition is observed at about 38.5 K by magnetization measurement without shift induced by a small amount of doping Al.Magnetodielectric effect is found near TN in each of the three compounds.The dielectric constant decreases and the magnetocapacitance increases with the increase of substitution of nonmagnetic Al3+ ions for the magnetic Cr3+ ions.The negative magnetocapacitive effect reaches ～ 13% for CuAl0.02Cr0.98S2.展开更多
The magnetic and dielectric properties of polycrystalline Cd 1-x Fe x Cr 2 S 4 (0 ≤ x ≤ 0.9) are investigated.Upon substitution of Cd by Fe,the Curie temperature (T C) is increased while the saturation magnetization...The magnetic and dielectric properties of polycrystalline Cd 1-x Fe x Cr 2 S 4 (0 ≤ x ≤ 0.9) are investigated.Upon substitution of Cd by Fe,the Curie temperature (T C) is increased while the saturation magnetization is decreased.A low doping level of Fe increases the permittivity,while a high doping level decreases the permittivity,which is explained by the internal barrier layer capacitor model.Kinks are observed in the temperature-dependent permittivity and loss tangent near T C for the samples with x=0.5,0.7,0.9,implying the existence of the magnetodielectric effect.Furthermore,with the increase of Fe content,a decrease of anomaly deviation rate induced by internal molecular field is revealed in the permittivity,while an increase is observed for the loss tangent.展开更多
Ternary yttrium chromium sulfide,Y2CrS4,prepared by the solid-state reaction of Y2S3,Cr,and S,was found to exhibit an antiferromagnetic transition at about 64 K.The X-ray diffraction pattern at 300 K was refined with ...Ternary yttrium chromium sulfide,Y2CrS4,prepared by the solid-state reaction of Y2S3,Cr,and S,was found to exhibit an antiferromagnetic transition at about 64 K.The X-ray diffraction pattern at 300 K was refined with space group Pca2 1,and the structure parameters were determined to be a = 12.51 ,b = 7.53,and c = 12.49.We investigated the magnetotransport properties,and observed negative colossal magnetoresistance reaching up to 2.5 × 10 4 % in the semiconducting compound of Y2CrS4.展开更多
The crystallographic structure and magnetic properties of La(Fe 11.4 Al 1.6 )C 0.02 are studied by magnetic measure- ment and powder neutron diffraction with temperature and applied magnetic field. Rietveld refinement...The crystallographic structure and magnetic properties of La(Fe 11.4 Al 1.6 )C 0.02 are studied by magnetic measure- ment and powder neutron diffraction with temperature and applied magnetic field. Rietveld refinement shows that La(Fe 11.4 Al 1.6 )C 0.02 crystallizes into the cubic NaZn 13 -type with two different Fe sites: Fe I (8b) and Fe II (96i), and that Al atoms preferentially occupy the Fe II site. A ferromagnetic state can be induced at a medial temperature of 39 K–139 K by an external magnetic field of 0.7 T, and a large lattice is correspondingly found at 100 K and 0.7 T. In all other conditions, La(Fe 11.4 Al 1.6 )C 0.02 has no net magnetization in the paramagnetic (T > T N = 182 K) or antifer- romagnetic states, and thus keeps its small lattice. Analysis of the Fe–Fe bond length indicates that the ferromagnetic state prefers longer Fe–Fe distances.展开更多
This paper investigates the single-molecule magnets of pure and Cr/Fe-doped Mn 12 -Ac. The components of the mixed crystals are identified by AC susceptibility technique. The ground-state spin and anisotropy parameter...This paper investigates the single-molecule magnets of pure and Cr/Fe-doped Mn 12 -Ac. The components of the mixed crystals are identified by AC susceptibility technique. The ground-state spin and anisotropy parameters of doped Mn 12 -Ac are obtained: (i) Mn 11 Cr-Ac (S=19/2, D=0.62 K, B=0.0009 K, =63 K), and (ii) Mn 11 Fe-Ac (S=21/2, D=0.39 K, B=0.001 K, =55 K). The single-ion origin of the magnetic anisotropy is discussed.展开更多
Crystallographic structure, magnetic properties, and magnetic entropy change of the Cr-based spinel sulfides Co_(1-x)Cu_xCr_2S_4(x = 0–0.8) have been investigated. All these compounds crystallize into the cubic spine...Crystallographic structure, magnetic properties, and magnetic entropy change of the Cr-based spinel sulfides Co_(1-x)Cu_xCr_2S_4(x = 0–0.8) have been investigated. All these compounds crystallize into the cubic spinel structure, the Cu substitution shrinks linearly the lattice constant at a ratio of 0.0223 per Cu atom in the unit cell, and enhances linearly the Curie temperature and the spontaneous magnetization at the rates of 18K and 0.33 μB/f.u. per Cu atom in the unit cell,respectively. All these compounds show a typical behavior of second order magnetic transition, and a room temperature magnetic entropy change of 2.57 J/kg·K is achieved for Co_(0.4)Cu_(0.6)Cr_2S_4.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.12074023,12304053,and 12174018)the Large Scientific Facility Open Subject of Songshan Lake(Dongguan,Guangdong)the Fundamental Research Funds for the Central Universities in China。
文摘Determination of the magnetic structure and confirmation of the presence or absence of inversion(P)and time reversal(Τ)symmetry is imperative for correctly understanding the topological magnetic materials.Here highquality single crystals of the layered manganese pnictide CaMnSb_(2)are synthesized using the self-flux method.
文摘The thermally assisted resonant tunnelling in a single crystal (Mno.96Cro.04)12-ac is studied in this paper. The obtained hysteresis loops at seven different temperatures between 1.8 and 3K show obvious dependence on temperature.The magnetization steps occur at specific field values of nHR with HR≈0.46T, which are approximately independent of the temperature. As the temperature decreases, the area enclosed in the hysteresis loops and the actual number n of the resonances increase, which provides clear evidence of thermally assisted resonant tunnelling in (Mn0.96Cr0.04)12-ac.
基金Project supported by the National Basic Research Program of China (973 Program) (Grant No. 2010CB833102)the Knowledge Innovation Project of the Chinese Academy of Sciencesthe National Natural Science Foundation of China (Grant Nos. 10974244 and 11004204)
文摘Hydrogenation, crystal structure and magnetic properties of La(Fe0.91Si0.09)13H(D)y have been studied by pressure-composition isotherms (PCI), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and magnetization measurements. The maximum absorption capacity is found to be 1.9 H(D) atoms per formula unit as a solid solution. All hydrides and deuterides crystallize in the NaZn13-type cubic structure with the lattice parameter increasing linearly with H(D) concentration. The H(D) absorption enhances the Curie temperature significantly. The magnetic entropy change of the highly H-absorbed compound La(Fe0.91Si0.09)13H1.81 reaches ～26 J/kg·K under a magnetic field change of 5 T near the Curie temperature TC = 350 K. No observable isotope effect seems to imply that only the magnetovolume effect is responsible for the strong interplay between magnetism and lattice.
基金Project supported by the National Key R&D Program of China(Grant No.2016YFA0401503)the National Materials Genome Project of China(Grant No.2016YFB0100106)the National Natural Science Foundation of China(Grant No.11675255)
文摘During the past decades,Li-ion batteries have been one of the most important energy storage devices.Large-scale energy storage requires Li-ion batteries which possess high energy density,low cost,and high safety.Other than advanced battery materials,in-depth understanding of the intrinsic mechanism correlated with cell reaction is also essential for the development of high-performance Li-ion battery.Advanced characterization techniques,especially neutron-based techniques,have greatly promoted Li-ion battery researches.In this review,the characteristics or capabilities of various neutron-based characterization techniques,including elastic neutron scattering,quasi-elastic neutron scattering,neutron imaging,and inelastic neutron scattering,for the related Li-ion-battery researches are summarized.The design of in-situ/operando environment is also discussed.The comprehensive survey on neutron-based characterizations for mechanism understanding will provide guidance for the further study of high-performance Li-ion batteries.
基金Project supported by the National Basic Research Program of China(Grant No.2010CB833102)the National Natural Science Foundation of China(Grant Nos.10974244+1 种基金11274369and 11104337)
文摘In this paper, multiferroics and magnetocapacitive effect of triangular-lattice antiferromagnet Ag Al0.02Cr0.98S2 are investigated by magnetic, ferroelectric, pyroelectric current and dielectric measurement. We find that it is a multiferroic material and the magnetocapacitive effect reaches a factor of up to 90 in an external field of 7 T. The results imply the further possibility of synthesizing the magnetocapacitive materials by modifying the frustrated spin structure in terms of a few B-site doping nonmagnetic ions.
基金Project supported by the National Basic Research Program of China (Grant No. 2010CB833102)the National Natural Science Foundation of China (Grant No. 10974244)
文摘In this paper,magnetic and dielectric properties of the quasi-two-dimensional triangular-lattice system CuCrS2 and its B-site-diluted analogs CuAl1?xCrxS2(x = 0.01 and x = 0.02) are investigated.Antiferromagnetic phase transition is observed at about 38.5 K by magnetization measurement without shift induced by a small amount of doping Al.Magnetodielectric effect is found near TN in each of the three compounds.The dielectric constant decreases and the magnetocapacitance increases with the increase of substitution of nonmagnetic Al3+ ions for the magnetic Cr3+ ions.The negative magnetocapacitive effect reaches ～ 13% for CuAl0.02Cr0.98S2.
基金Project supported by the National Natural Science Foundation of China (Grant No.10874228)the National Basic Research Program of China (Grant No.2010CB833102)
文摘The magnetic and dielectric properties of polycrystalline Cd 1-x Fe x Cr 2 S 4 (0 ≤ x ≤ 0.9) are investigated.Upon substitution of Cd by Fe,the Curie temperature (T C) is increased while the saturation magnetization is decreased.A low doping level of Fe increases the permittivity,while a high doping level decreases the permittivity,which is explained by the internal barrier layer capacitor model.Kinks are observed in the temperature-dependent permittivity and loss tangent near T C for the samples with x=0.5,0.7,0.9,implying the existence of the magnetodielectric effect.Furthermore,with the increase of Fe content,a decrease of anomaly deviation rate induced by internal molecular field is revealed in the permittivity,while an increase is observed for the loss tangent.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10375088 and 10505029）. Acknowledgment The authors thank Dr Denis Sheptyakov at PSI for much support of the neutron diffraction experiments.
基金Project supported by the National Basic Research Program of China (Grant No. 2010CB833102)the National Natural ScienceFoundation of China (Grant No. 10974244)
文摘Ternary yttrium chromium sulfide,Y2CrS4,prepared by the solid-state reaction of Y2S3,Cr,and S,was found to exhibit an antiferromagnetic transition at about 64 K.The X-ray diffraction pattern at 300 K was refined with space group Pca2 1,and the structure parameters were determined to be a = 12.51 ,b = 7.53,and c = 12.49.We investigated the magnetotransport properties,and observed negative colossal magnetoresistance reaching up to 2.5 × 10 4 % in the semiconducting compound of Y2CrS4.
基金supported by the National Basic Research Program of China (973 Program) (Grant No. 2010CB833102)the National Natural Science Foundation of China (Grant No. 10974244)
文摘The crystallographic structure and magnetic properties of La(Fe 11.4 Al 1.6 )C 0.02 are studied by magnetic measure- ment and powder neutron diffraction with temperature and applied magnetic field. Rietveld refinement shows that La(Fe 11.4 Al 1.6 )C 0.02 crystallizes into the cubic NaZn 13 -type with two different Fe sites: Fe I (8b) and Fe II (96i), and that Al atoms preferentially occupy the Fe II site. A ferromagnetic state can be induced at a medial temperature of 39 K–139 K by an external magnetic field of 0.7 T, and a large lattice is correspondingly found at 100 K and 0.7 T. In all other conditions, La(Fe 11.4 Al 1.6 )C 0.02 has no net magnetization in the paramagnetic (T > T N = 182 K) or antifer- romagnetic states, and thus keeps its small lattice. Analysis of the Fe–Fe bond length indicates that the ferromagnetic state prefers longer Fe–Fe distances.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10505029 and 10375088)
文摘This paper investigates the single-molecule magnets of pure and Cr/Fe-doped Mn 12 -Ac. The components of the mixed crystals are identified by AC susceptibility technique. The ground-state spin and anisotropy parameters of doped Mn 12 -Ac are obtained: (i) Mn 11 Cr-Ac (S=19/2, D=0.62 K, B=0.0009 K, =63 K), and (ii) Mn 11 Fe-Ac (S=21/2, D=0.39 K, B=0.001 K, =55 K). The single-ion origin of the magnetic anisotropy is discussed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11274369,51472210,and 11675255)
文摘Crystallographic structure, magnetic properties, and magnetic entropy change of the Cr-based spinel sulfides Co_(1-x)Cu_xCr_2S_4(x = 0–0.8) have been investigated. All these compounds crystallize into the cubic spinel structure, the Cu substitution shrinks linearly the lattice constant at a ratio of 0.0223 per Cu atom in the unit cell, and enhances linearly the Curie temperature and the spontaneous magnetization at the rates of 18K and 0.33 μB/f.u. per Cu atom in the unit cell,respectively. All these compounds show a typical behavior of second order magnetic transition, and a room temperature magnetic entropy change of 2.57 J/kg·K is achieved for Co_(0.4)Cu_(0.6)Cr_2S_4.
