Kagome magnets have attracted considerable research attention due to the interplay between topology,magnetism and electronic correlations.In this study we report single-crystal synthesis of a series of the kagome magn...Kagome magnets have attracted considerable research attention due to the interplay between topology,magnetism and electronic correlations.In this study we report single-crystal synthesis of a series of the kagome magnets.RCr_(6)Ge_(6)(R=Gd-Tm) that possess defect-free Cr kagome lattices and systematically study their magnetic and electrical transport properties.The transition from a canted ferrimagnetic to a paramagnetic state in GdCr_(6)Ge_(6),TbCr_(6)Ge_(6),DyCr_(6)Ge_(6),HoCr_(6)Ge_(6),ErCr_(6)Ge_(6) and TmCr_(6)Ge_(6) occurs at 11.3 K,10.8 K,4.3 K,2.5 K,3.3 K and below 2 K,respectively,due to R-R interactions within the compounds.Magnetization measurements reveal highly anisotropic magnetism with canted magnetic moments in these compounds.In electrical transport,both negative and positive magnetoresistances at different magnetic fields and temperatures have been observed due to the competition between different scattering mechanisms.This work enriches our understanding of the Cr-based kagome magnets and paves the way to search for possible topological responses in this family.展开更多
Due to the lack of inversion,mirror or other roto-inversion symmetries,chiral crystals possess a well-defined handedness which,when combined with time-reversal symmetry breaking from the application of magnetic fields...Due to the lack of inversion,mirror or other roto-inversion symmetries,chiral crystals possess a well-defined handedness which,when combined with time-reversal symmetry breaking from the application of magnetic fields,can give rise to directional dichroism of the electrical transport phenomena via the magnetochiral anisotropy.In this study,we investigate the nonreciprocal magneto-transport in microdevices of NbGe_(2),a superconductor with structural chirality.A giant nonreciprocal signal from vortex motions is observed during the superconducting transition,with the ratio of nonreciprocal resistance to the normal resistanceγreaching 6×10^(5)T^(-1)·A^(-1).Interestingly,the intensity can be adjusted and even sign-reversed by varying the current,the temperature,and the crystalline orientation.Our findings illustrate intricate vortex dynamics and offer ways of manipulation on the rectification effect in superconductors with structural chirality.展开更多
A lithium(Li)vapour layer was formed around a flowing liquid Li limiter to shield against the plasma incident power and reduce limiter heat flux in the EAST tokamak.The results revealed that after a plasma operation o...A lithium(Li)vapour layer was formed around a flowing liquid Li limiter to shield against the plasma incident power and reduce limiter heat flux in the EAST tokamak.The results revealed that after a plasma operation of a few seconds,the layer became clear,which indicated a strong Li emission with a decrease in the limiter surface temperature.This emission resulted in a dense vapour around the limiter,and Li ions moved along the magnetic fleld to form a green shielding layer on the limiter.The plasma heat flux loaded on the limiter,measured by the probe installed on the limiter,was approximately 52%lower than that detected by a fast-reciprocating probe at the same radial position without the limiter in EAST.Additionally,approximately 42%of the parallel heat flux was dissipated directly with the enhanced Li radiation in the discharge with the liquid metal infused trenches(LIMIT)limiter.This observation revealed that the Li vapour layer exhibited an excellent shielding effect to liquid Li on plasma heat flux,which is a possible beneflt of liquid-plasma-facing components in future fusion devices.展开更多
Transition metal and rare earth intermetallics have been a fertile playground for research of various quantum states.We report detailed magnetic studies on Sm Mn_(2)Ge_(2),an anisotropic itinerant magnet with multiple...Transition metal and rare earth intermetallics have been a fertile playground for research of various quantum states.We report detailed magnetic studies on Sm Mn_(2)Ge_(2),an anisotropic itinerant magnet with multiple magnetic phases.The critical behavior of the ferromagnetic phase transition is investigated by employing the modified Arrott plot with the Kouvel-Fisher method.The critical temperature TCis determined to be around 342.7 K with critical exponents ofβ=0.417 andγ=1.122,and the interaction function is found to be J(r)~r^(-4.68),suggesting the coexistence of long-range and shortrange magnetic interactions.Our results contribute to the understanding of complex magnetism in Sm Mn_(2)Ge_(2),which may provide fundamental guidance in future spintronic applications.展开更多
We report magnetization and Raman spectroscopy study on single crystals of VOCl,a van der Waals antiferromagnetic material.Magnetization measurement confirms an antiferromagnetic transition at 79 K and a magnetic easy...We report magnetization and Raman spectroscopy study on single crystals of VOCl,a van der Waals antiferromagnetic material.Magnetization measurement confirms an antiferromagnetic transition at 79 K and a magnetic easy axis along crystallographic a direction.The temperature-dependent Raman spectrum reveals five peaks at 30 K.Below the Neel temperature TN,the Raman-active modes 247 cm^(−1) and 404 cm^(−1) remarkably deviate from the standard Boltzmann function,which is ascribed to the strong magnetoelastic coupling between spins and phonons.We further observe an anomaly in 383 cm^(−1) mode at around 150 K.This coincides with the broad maximum in VOCl’s magnetic susceptibility,suggesting a development of short-ranged magnetic order at this temperature.展开更多
Geometrical frustration in low-dimensional magnetic systems has been an intriguing research aspect,where the suppression of conventional magnetic order may lead to exotic ground states such as spin glass or spin liqui...Geometrical frustration in low-dimensional magnetic systems has been an intriguing research aspect,where the suppression of conventional magnetic order may lead to exotic ground states such as spin glass or spin liquid.In this work we report the synthesis and magnetism study of the monocrystalline Mn_(2)Ga_(2)S_(5),featuring both the van derWaals structure and a bilayered triangular Mn lattice.Magnetic susceptibility reveals a significant antiferromagnetic interaction with a Curie-Weiss temperature θ_(w)~-260 K and a high spin S=5/2 Mn^(2+) state.However,no long range magnetic order has been found down to 2 K,and a spin freezing transition is found to occur at around 12 K well below its θ_(w).This yields a frustration index of f=-θ_(w)/T_(f)≈22,an indication that the system is highly frustrated.The absence of a double-peak structure in magnetic specific heat compared with the TM_(2)S_(4) compounds implies that the spin freezing behavior in Mn_(2)Ga_(2)S_(5)is a result of the competition between exchange interactions and the 2D crystalline structure.Our results suggest that the layered Mn_(2)Ga_(2)S_(5)would be an excellent candidate for investigating the physics of 2D magnetism and spin disordered state.展开更多
Nanoscale zerovalent iron/magnetic carbon(NZVI/MC) composites were successfully synthesized by simply calcining yellow pine and iron precursors. NZVI/MC pyrolyzed at 800°C(NZVI/MC800) had a higher percentage of N...Nanoscale zerovalent iron/magnetic carbon(NZVI/MC) composites were successfully synthesized by simply calcining yellow pine and iron precursors. NZVI/MC pyrolyzed at 800°C(NZVI/MC800) had a higher percentage of NZVI and displayed better resistance to aggregation and oxidation of NZVI than samples prepared at other temperatures. The NZVI/MC800 material was applied for the elimination of U(Ⅵ) from aqueous solutions. The results suggested that the NZVI/MC800 displayed excellent adsorption capacity(203.94 mg/g)toward U(Ⅵ). The significant adsorption capacity and fast adsorption kinetics were attributed to the presence of well-dispersed NZVI, which could quickly reduce U(Ⅵ) into U(Ⅳ), trapping the guest U(Ⅳ) in the porous biocarbon matrix. The removal of U(Ⅵ) on the NZVI/MC samples was strongly affected by solution pH. The NZVI/MC samples also displayed outstanding reusability for U(Ⅵ) removal after multiple cycles. These findings indicate that NZVI/MC has great potential for remediation of wastewater containing U(Ⅵ).展开更多
基金Project supported by the National Key R&D Program of China(Grant No.2021YFA1600204)the National Natural Science Foundation of China(Grant Nos.U2032213,12104461,12374129,12304156,and 52325105)+1 种基金Chinese Academy of Sciences(Grant Nos.YSBR-084 and JZHKYPT2021-08)supported by the High Magnetic Field Laboratory of Anhui Province。
文摘Kagome magnets have attracted considerable research attention due to the interplay between topology,magnetism and electronic correlations.In this study we report single-crystal synthesis of a series of the kagome magnets.RCr_(6)Ge_(6)(R=Gd-Tm) that possess defect-free Cr kagome lattices and systematically study their magnetic and electrical transport properties.The transition from a canted ferrimagnetic to a paramagnetic state in GdCr_(6)Ge_(6),TbCr_(6)Ge_(6),DyCr_(6)Ge_(6),HoCr_(6)Ge_(6),ErCr_(6)Ge_(6) and TmCr_(6)Ge_(6) occurs at 11.3 K,10.8 K,4.3 K,2.5 K,3.3 K and below 2 K,respectively,due to R-R interactions within the compounds.Magnetization measurements reveal highly anisotropic magnetism with canted magnetic moments in these compounds.In electrical transport,both negative and positive magnetoresistances at different magnetic fields and temperatures have been observed due to the competition between different scattering mechanisms.This work enriches our understanding of the Cr-based kagome magnets and paves the way to search for possible topological responses in this family.
基金Project supported by the National Key R&D Program of China(Grant No.2022YFA1403603)the National Natural Science Foundation of China(Grant Nos.U2032213,12104461,12374129,and 12304156)+1 种基金Chinese Academy of Sciences(Grant Nos.YSBR-084,and JZHKYPT-2021-08)A portion of this work was supported by the High Magnetic Field Laboratory of Anhui Province.
文摘Due to the lack of inversion,mirror or other roto-inversion symmetries,chiral crystals possess a well-defined handedness which,when combined with time-reversal symmetry breaking from the application of magnetic fields,can give rise to directional dichroism of the electrical transport phenomena via the magnetochiral anisotropy.In this study,we investigate the nonreciprocal magneto-transport in microdevices of NbGe_(2),a superconductor with structural chirality.A giant nonreciprocal signal from vortex motions is observed during the superconducting transition,with the ratio of nonreciprocal resistance to the normal resistanceγreaching 6×10^(5)T^(-1)·A^(-1).Interestingly,the intensity can be adjusted and even sign-reversed by varying the current,the temperature,and the crystalline orientation.Our findings illustrate intricate vortex dynamics and offer ways of manipulation on the rectification effect in superconductors with structural chirality.
基金funded by the National Key Research and Development Program of China(No.2017YFE0301100)National Natural Science Foundation of China(Nos.11905138,11905148 and 11905254)+2 种基金the U.S.Dept.of Energy contract DE-AC02-09CH11466 and grant DESC0016553Users with Excellence Program of Hefei Science Center CAS(No.2020HSC-UE010)Interdisciplinary and Collaborative Teams of CAS。
文摘A lithium(Li)vapour layer was formed around a flowing liquid Li limiter to shield against the plasma incident power and reduce limiter heat flux in the EAST tokamak.The results revealed that after a plasma operation of a few seconds,the layer became clear,which indicated a strong Li emission with a decrease in the limiter surface temperature.This emission resulted in a dense vapour around the limiter,and Li ions moved along the magnetic fleld to form a green shielding layer on the limiter.The plasma heat flux loaded on the limiter,measured by the probe installed on the limiter,was approximately 52%lower than that detected by a fast-reciprocating probe at the same radial position without the limiter in EAST.Additionally,approximately 42%of the parallel heat flux was dissipated directly with the enhanced Li radiation in the discharge with the liquid metal infused trenches(LIMIT)limiter.This observation revealed that the Li vapour layer exhibited an excellent shielding effect to liquid Li on plasma heat flux,which is a possible beneflt of liquid-plasma-facing components in future fusion devices.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFA1600204)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302802)+2 种基金the National Natural Science Foundation of China(Grant Nos.U1832214,U2032213,12104461,and 12074135)the High Magnetic Field Laboratory of Anhuisupported by the Start-up Project of Anhui University(Grant No.S020318001/020)。
文摘Transition metal and rare earth intermetallics have been a fertile playground for research of various quantum states.We report detailed magnetic studies on Sm Mn_(2)Ge_(2),an anisotropic itinerant magnet with multiple magnetic phases.The critical behavior of the ferromagnetic phase transition is investigated by employing the modified Arrott plot with the Kouvel-Fisher method.The critical temperature TCis determined to be around 342.7 K with critical exponents ofβ=0.417 andγ=1.122,and the interaction function is found to be J(r)~r^(-4.68),suggesting the coexistence of long-range and shortrange magnetic interactions.Our results contribute to the understanding of complex magnetism in Sm Mn_(2)Ge_(2),which may provide fundamental guidance in future spintronic applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2032213,U1832214,and 11774352)。
文摘We report magnetization and Raman spectroscopy study on single crystals of VOCl,a van der Waals antiferromagnetic material.Magnetization measurement confirms an antiferromagnetic transition at 79 K and a magnetic easy axis along crystallographic a direction.The temperature-dependent Raman spectrum reveals five peaks at 30 K.Below the Neel temperature TN,the Raman-active modes 247 cm^(−1) and 404 cm^(−1) remarkably deviate from the standard Boltzmann function,which is ascribed to the strong magnetoelastic coupling between spins and phonons.We further observe an anomaly in 383 cm^(−1) mode at around 150 K.This coincides with the broad maximum in VOCl’s magnetic susceptibility,suggesting a development of short-ranged magnetic order at this temperature.
基金supported by the National Natural Science Foundation of China(Grant Nos.U1832214,11774007,U2032213,and 12104461).
文摘Geometrical frustration in low-dimensional magnetic systems has been an intriguing research aspect,where the suppression of conventional magnetic order may lead to exotic ground states such as spin glass or spin liquid.In this work we report the synthesis and magnetism study of the monocrystalline Mn_(2)Ga_(2)S_(5),featuring both the van derWaals structure and a bilayered triangular Mn lattice.Magnetic susceptibility reveals a significant antiferromagnetic interaction with a Curie-Weiss temperature θ_(w)~-260 K and a high spin S=5/2 Mn^(2+) state.However,no long range magnetic order has been found down to 2 K,and a spin freezing transition is found to occur at around 12 K well below its θ_(w).This yields a frustration index of f=-θ_(w)/T_(f)≈22,an indication that the system is highly frustrated.The absence of a double-peak structure in magnetic specific heat compared with the TM_(2)S_(4) compounds implies that the spin freezing behavior in Mn_(2)Ga_(2)S_(5)is a result of the competition between exchange interactions and the 2D crystalline structure.Our results suggest that the layered Mn_(2)Ga_(2)S_(5)would be an excellent candidate for investigating the physics of 2D magnetism and spin disordered state.
基金supported by the National Natural Science Foundation of China (No.21477133)the Key Lab of Photovoltaic and Energy Conservation Materials,Chinese Academy of Sciences is acknowledged
文摘Nanoscale zerovalent iron/magnetic carbon(NZVI/MC) composites were successfully synthesized by simply calcining yellow pine and iron precursors. NZVI/MC pyrolyzed at 800°C(NZVI/MC800) had a higher percentage of NZVI and displayed better resistance to aggregation and oxidation of NZVI than samples prepared at other temperatures. The NZVI/MC800 material was applied for the elimination of U(Ⅵ) from aqueous solutions. The results suggested that the NZVI/MC800 displayed excellent adsorption capacity(203.94 mg/g)toward U(Ⅵ). The significant adsorption capacity and fast adsorption kinetics were attributed to the presence of well-dispersed NZVI, which could quickly reduce U(Ⅵ) into U(Ⅳ), trapping the guest U(Ⅳ) in the porous biocarbon matrix. The removal of U(Ⅵ) on the NZVI/MC samples was strongly affected by solution pH. The NZVI/MC samples also displayed outstanding reusability for U(Ⅵ) removal after multiple cycles. These findings indicate that NZVI/MC has great potential for remediation of wastewater containing U(Ⅵ).
