While the ferroelectricity in type-II multiferroic rare-earth manganites is believed to be generated by the inverse Dzyaloshinskii-Moriya （DM） interaction （spin orbit coupling） associated with the Mn spiral spin o...While the ferroelectricity in type-II multiferroic rare-earth manganites is believed to be generated by the inverse Dzyaloshinskii-Moriya （DM） interaction （spin orbit coupling） associated with the Mn spiral spin order, recent results revealed the strong spin-lattice coupling arising from the Dy-Mn spin interaction in DyMn03, which may also be an ingredient contributing to the ferroelectricity. In this work, we summarize our recent experiments on this issue by performing a series of rare-earth site nonmagnetic Y and magnetic Ho substitutions at Dy site for DyMn03. It is demonstrated that the Dy Mn spin interaction contributes to the ferroelectric polarization through the symmetric exchange striction mechanism （spin-lattice coupling）. A coexistence of the spin orbit coupling and spin-lattice coupling in one compound is confirmed. At the same time, the independent Dy antiferromagnetic spin order at low temperature can be effectively suppressed by the substitutions, beneficial to the polarization enhancement.展开更多
The high Li-ion conductivity of the Li7P3S11 sulfide-based solid electrolyte makes it a promising candidate for all-solid-state lithium batteries. The Li-ion transport over electrode-electrolyte and electrolyteelectro...The high Li-ion conductivity of the Li7P3S11 sulfide-based solid electrolyte makes it a promising candidate for all-solid-state lithium batteries. The Li-ion transport over electrode-electrolyte and electrolyteelectrolyte interfaces, vital for the performance of solid-state batteries, is investigated by impedance spectroscopy and solid-state NMR experiments. An all-solid-state Li-ion battery is assembled with the Li7P3S11 electrolyte, nano-Li2S cathode and Li-In foil anode, showing a relatively large initial discharge capacity of 1139.5 m Ah/g at a current density of 0.064 m A/cm^ 2 retaining 850.0 m Ah/g after 30 cycles. Electrochemical impedance spectroscopy suggests that the decrease in capacity over cycling is due to the increased interfacial resistance between the electrode and the electrolyte. 1D exchange ^7Li NMR quantifies the interfacial Li-ion transport between the uncycled electrode and the electrolyte, resulting in a diffusion coefficient of 1.70(3) ×10^-14cm^2/s at 333 K and an energy barrier of 0.132 e V for the Li-ion transport between Li2S cathode and Li7P3S11 electrolyte. This indicates that the barrier for Li-ion transport over the electrode-electrolyte interface is small. However, the small diffusion coefficient for Li-ion diffusion between the Li2S and the Li7P3S11 suggests that these contact interfaces between electrode and electrolyte are relatively scarce, challenging the performance of these solid-state batteries.展开更多
Experiments including C-13 spin-lattice relaxation, C-13 heteronuclear dipolar dephasing and H-1 spin diffusion are performed on poly (2,6-dimethyl-1,4-phenylene oxide) (PPO). The results show that the rotation of the...Experiments including C-13 spin-lattice relaxation, C-13 heteronuclear dipolar dephasing and H-1 spin diffusion are performed on poly (2,6-dimethyl-1,4-phenylene oxide) (PPO). The results show that the rotation of the methyl groups in solid PPO is partially restricted, which results in a surprisingly efficient spin diffusion between the aromatic proton and methyl proton characterized by a diffusion time of 150 mu s. The results also show that the aromatic ring in solid PPO is rigid and twisted, which causes all aromatic carbons to be chemically unequivalent.展开更多
The ^(13)C T_(1s) of --CH_3 side group in PPU/P (St-co-AA), AB-crosslinked polymers (i. e.ABCP) was studied by using high resolution solid state NMR. The rotation motion of --CH_3 sidegroup in PPU was analyzed by mean...The ^(13)C T_(1s) of --CH_3 side group in PPU/P (St-co-AA), AB-crosslinked polymers (i. e.ABCP) was studied by using high resolution solid state NMR. The rotation motion of --CH_3 sidegroup in PPU was analyzed by means of the average spectral density functions of internal rota-tion. The results showed that the rotation of the --CH_3 side group is related closely to the com-patibility between the two components. The compatibility was studied by analyzing the protonspin-lattice relaxation in rotating frame, spin-spin relaxation and spin-diffusion. The resultsshowed that the hydrogen bonds between the components play a major role in determining thecompatibility. Through spin diffusion studying, the soft phase domain size was calculated. Bystudying proton spin-spin relaxation, the content of each component in each phase and that ofeach phase in the samples can be obtained. The result shows that the content of interphase is related closely to the compatibility.展开更多
Graphene is of great interest because of its exciting properties and potential applications,but its production on a large-scale still presents considerable challenges.Herein,we report the synthesis of predominately fe...Graphene is of great interest because of its exciting properties and potential applications,but its production on a large-scale still presents considerable challenges.Herein,we report the synthesis of predominately few-layer graphene,due toπ–πstacking,and single-layer graphene from reaction between hexabromobenzene and Na metal,followed by annealing to improve crystallinity.The reaction proceeds via a free-radical C(sp^(2))–C(sp^(2))coupling mechanism,which is supported by theoretical calculations.The graphene can host unpaired spin electrons,leading to a short acquisition time for a solidstate nuclear magnetic resonance 13C spectrum from unlabeled graphene,which is ascribed to the very short spin-lattice relaxation time.High catalytic activity for transforming amine to imine with a conversion of>99%and a yield of∼97%is demonstrated,and high electronic conductivity of∼105 S·m^(−1) is found by terahertz spectroscopy.The reaction delivers a method for synthesizing graphene with a high spin concentration from perbrominated benzene molecules by using an active metallic agent,such as Na,Li,or Mg.展开更多
The dynamics of a series of poly(n-alkyl methacrylates) is investigated by means of ^(13)C spin-lattice relaxation experiments. The results show that the dynamics has the polymer property dependence.
The compatibility and dynamics of latex bidirectional/nterpenetrating polymer networks (LBIPNs) and latex IPN(LIPN) of poly(vinyl acetate)(PVAc) and poly (butyl acrylate )(PBA) are investigated by means of dynamic mec...The compatibility and dynamics of latex bidirectional/nterpenetrating polymer networks (LBIPNs) and latex IPN(LIPN) of poly(vinyl acetate)(PVAc) and poly (butyl acrylate )(PBA) are investigated by means of dynamic mechanical spectroscopy (DMS) and nuclear magnetic resonance (NMR) techniques. The results of DMS show that the compatibility of the LBIPNs is much better than that of the corresponding LIPN and depends to, a large extent on the distribution of PVAc both in the core and in the shell. The results of NMR measurements indicate that the rotational correlation times of the side- groups of PBA in the LBIPN are longer than those in the LIPN. The relation between the ^(13)C linewidths of PBA and temperature is also discussed.展开更多
C spin-lattice relaxtion times for polystyrene nanolatex particles have been investigated. It was found that the dramatic increase at 80℃ annealing temperature is well below the Tg temperature of bulk polystyrene, t...C spin-lattice relaxtion times for polystyrene nanolatex particles have been investigated. It was found that the dramatic increase at 80℃ annealing temperature is well below the Tg temperature of bulk polystyrene, the increase of relaxation time of aromatic carbons is larger than that of for aliphatic carbons at transition annealing temperature.展开更多
Nine Ln( Ⅲ ) complexes with a novel Schiff base derived from diglycolamine and benzoylacetone (BZDA) have been synthesized and characterized. They can be formulated as [Ln2(BZDA)3(NO3)3](NO3)3· nH2O(Ln=La, Pr, N...Nine Ln( Ⅲ ) complexes with a novel Schiff base derived from diglycolamine and benzoylacetone (BZDA) have been synthesized and characterized. They can be formulated as [Ln2(BZDA)3(NO3)3](NO3)3· nH2O(Ln=La, Pr, Nd, Sm, n = 4; Ln=Gd, Tb, Er, Yb, Y, n = l). Enamic form mechanism in this β-diketone Schiff base and its complexes were suggested and proved by IR, UV and NMR methods. The 13C spin-lattice relaxation time T1 and the ratios of r(ci-Ln)/r(cj-Ln) were measured by a 500 MHz NMR instrument for elucidating the formation of the stable sk-membered chelate ring structure in these complexes. The EPR spectrum of the Gd( Ⅲ ) complex exhibits the 'U' spectral feature and 'zero field effect'. On the basis of them, the crystal field strength and the local symmetry around Gd3+ in the complex have been discussed.展开更多
Fatty acids such as oleic and stearic acids having a long hydrocarbon chain are known to exist as dimers in their melt and even in a non-polar solvent. In their melt the dimers arrange longitudinally and alternately t...Fatty acids such as oleic and stearic acids having a long hydrocarbon chain are known to exist as dimers in their melt and even in a non-polar solvent. In their melt the dimers arrange longitudinally and alternately to form clusters which resemble a smectic liquid crystal. The clusters determine the liquid properties of the fatty acids such as density, viscosity and fluidity. Then, do the dimers of fatty acid having a moderate-length hydrocarbon chain construct such the clusters? In the present study the dynamic molecular behavior and assembly structure of octanoic acid in its melt and also in CCl4 solution have been investigated by the X-ray diffraction, near infrared spectroscopy, 1H-NMR chemical shift, self-diffusion coefficient and 13C-NMR spin-lattice relaxation time measurements. From these results it has been revealed that the clusters of octanoic acid exist in its melt and also in CCl4 and that the clusters in the melt disintegrate with an increase in temperature. The dissociation profile of dimers of octanoic acid into monomers in CCl4 also has been clarified.展开更多
Spin-lattice (SL) coupling plays an important role in spintronic applications given its effects on magnetic,ferroelectric,optical,and thermodynamic properties.Experiments and theoretical calculations have revealed a l...Spin-lattice (SL) coupling plays an important role in spintronic applications given its effects on magnetic,ferroelectric,optical,and thermodynamic properties.Experiments and theoretical calculations have revealed a large SL coupling effect in CrGeTe_(3) and CrI_(3) monolayers.However,the microscopic origin of SL coupling in these systems is still unclear.In this work,we develop a systematic method to explore the atomistic mechanism of SL coupling based on the density functional theory.We find that the first-and second-order SL couplings in ternary system CrGeTe_(3) are considerably stronger than those in binary system CrI_(3).For the first-order SL coupling,the Cr ions of the magnetic pair and Ge ions positively contribute to the strain enhancement of ferromagnetism in CrGeTe_(3).However,the Cr ions provide a negative contribution in CrI_(3).Furthermore,our tight-binding analysis suggests that the p-d hopping in CrGeTe_(3) gradually decreases with the tensile strain,rapidly enhancing the ferromagnetism under the tensile strain.The large frequency shifts in CrGeTe_(3) are caused by the large second-order exchange derivatives (one type of second-order SL coupling) of the Cr ions of the magnetic pair.展开更多
Ultrathin van der Waals(vdW)magnets provide a possibility to access magnetic ordering in the two-dimensional(2D)limit,which are expected to be applied in the spintronic devices.Raman spectroscopy is a powerful charact...Ultrathin van der Waals(vdW)magnets provide a possibility to access magnetic ordering in the two-dimensional(2D)limit,which are expected to be applied in the spintronic devices.Raman spectroscopy is a powerful characterization method to investigate the spin-related properties in 2D vdW magnets,including magnon and spin–lattice interaction,which are hardly accessible by other optical methods.In this paper,the recent progress of various magnetic properties in 2D vdW magnets studied by Raman spectroscopy is reviewed,including the magnetic transition,spin-wave,spin–lattice interaction,symmetry tuning induced by spin ordering,and nonreciprocal magneto-phonon Raman scattering.展开更多
According to a uniform and simple method of calculating spin-lattice coupling coefficients and the pert1rbation formulas of gi factors and hyperfine structure constants Ai based on the cluster approach for 3d7 ions in...According to a uniform and simple method of calculating spin-lattice coupling coefficients and the pert1rbation formulas of gi factors and hyperfine structure constants Ai based on the cluster approach for 3d7 ions in cubic,tetragonal and trigonal octahedral crystal fields, the spin-lattice coupling coefficients Fij (F11, Fl2, F44), Zij (Z11, Z12,Z44) and also g factor and hyperfine constant A for MgO:Co2+ are calculated by using the parameters obtained from the optical spectra without adjustable parameters. The calculated results show good agreement with the observed values.The difiiculty in explaining the coeficients Fij and Zij is therefore removed.展开更多
A new 3 d transition-metal molybdate-tellurite(NH4)2 Co(TeMo2O9)2 was obtained through a conventional hydrothermal method.This compound was confirmed to crystallize in the monoclinic system of space group P2_(1)/c wit...A new 3 d transition-metal molybdate-tellurite(NH4)2 Co(TeMo2O9)2 was obtained through a conventional hydrothermal method.This compound was confirmed to crystallize in the monoclinic system of space group P2_(1)/c with a=10.5133(5),b=10.6456(5),c=7.6078(5)Å,β=108.879(6)o,V=805.66(8)Å^(3),Z=2,M_(r)=1021.97,Dc=4.213 g/cm^(3),μ=7.685 mm^(–1),F(000)=930,the final R=0.0399 and w R=0.1025 for 1580 observed reflections with I>2σ(I),showing a tunnel structure with spin triangle-lattice composed by CoO_(6) octahedra.Magnetic and heat capacity measurements confirmed a paramagnetic behavior down to 2 K with a negative Weiss temperature of–20 K,suggesting remarkable spin frustration in the system.展开更多
文摘While the ferroelectricity in type-II multiferroic rare-earth manganites is believed to be generated by the inverse Dzyaloshinskii-Moriya （DM） interaction （spin orbit coupling） associated with the Mn spiral spin order, recent results revealed the strong spin-lattice coupling arising from the Dy-Mn spin interaction in DyMn03, which may also be an ingredient contributing to the ferroelectricity. In this work, we summarize our recent experiments on this issue by performing a series of rare-earth site nonmagnetic Y and magnetic Ho substitutions at Dy site for DyMn03. It is demonstrated that the Dy Mn spin interaction contributes to the ferroelectric polarization through the symmetric exchange striction mechanism （spin-lattice coupling）. A coexistence of the spin orbit coupling and spin-lattice coupling in one compound is confirmed. At the same time, the independent Dy antiferromagnetic spin order at low temperature can be effectively suppressed by the substitutions, beneficial to the polarization enhancement.
基金funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement no.[307161] of M.W.
文摘The high Li-ion conductivity of the Li7P3S11 sulfide-based solid electrolyte makes it a promising candidate for all-solid-state lithium batteries. The Li-ion transport over electrode-electrolyte and electrolyteelectrolyte interfaces, vital for the performance of solid-state batteries, is investigated by impedance spectroscopy and solid-state NMR experiments. An all-solid-state Li-ion battery is assembled with the Li7P3S11 electrolyte, nano-Li2S cathode and Li-In foil anode, showing a relatively large initial discharge capacity of 1139.5 m Ah/g at a current density of 0.064 m A/cm^ 2 retaining 850.0 m Ah/g after 30 cycles. Electrochemical impedance spectroscopy suggests that the decrease in capacity over cycling is due to the increased interfacial resistance between the electrode and the electrolyte. 1D exchange ^7Li NMR quantifies the interfacial Li-ion transport between the uncycled electrode and the electrolyte, resulting in a diffusion coefficient of 1.70(3) ×10^-14cm^2/s at 333 K and an energy barrier of 0.132 e V for the Li-ion transport between Li2S cathode and Li7P3S11 electrolyte. This indicates that the barrier for Li-ion transport over the electrode-electrolyte interface is small. However, the small diffusion coefficient for Li-ion diffusion between the Li2S and the Li7P3S11 suggests that these contact interfaces between electrode and electrolyte are relatively scarce, challenging the performance of these solid-state batteries.
文摘Experiments including C-13 spin-lattice relaxation, C-13 heteronuclear dipolar dephasing and H-1 spin diffusion are performed on poly (2,6-dimethyl-1,4-phenylene oxide) (PPO). The results show that the rotation of the methyl groups in solid PPO is partially restricted, which results in a surprisingly efficient spin diffusion between the aromatic proton and methyl proton characterized by a diffusion time of 150 mu s. The results also show that the aromatic ring in solid PPO is rigid and twisted, which causes all aromatic carbons to be chemically unequivalent.
基金The project was supported by the National Natural Science Foundation of China
文摘The ^(13)C T_(1s) of --CH_3 side group in PPU/P (St-co-AA), AB-crosslinked polymers (i. e.ABCP) was studied by using high resolution solid state NMR. The rotation motion of --CH_3 sidegroup in PPU was analyzed by means of the average spectral density functions of internal rota-tion. The results showed that the rotation of the --CH_3 side group is related closely to the com-patibility between the two components. The compatibility was studied by analyzing the protonspin-lattice relaxation in rotating frame, spin-spin relaxation and spin-diffusion. The resultsshowed that the hydrogen bonds between the components play a major role in determining thecompatibility. Through spin diffusion studying, the soft phase domain size was calculated. Bystudying proton spin-spin relaxation, the content of each component in each phase and that ofeach phase in the samples can be obtained. The result shows that the content of interphase is related closely to the compatibility.
基金This work was financially support from the National Key R&D Program of China(no.2016YFA0200200)the National Program on Key Basic Research Project(973 program,no.2013CB933804)+1 种基金the National Natural Science Foundation of China(no.21271112)the Tribology Science Fund of State Key Laboratory of Tribology(SKLTKF20B18).
文摘Graphene is of great interest because of its exciting properties and potential applications,but its production on a large-scale still presents considerable challenges.Herein,we report the synthesis of predominately few-layer graphene,due toπ–πstacking,and single-layer graphene from reaction between hexabromobenzene and Na metal,followed by annealing to improve crystallinity.The reaction proceeds via a free-radical C(sp^(2))–C(sp^(2))coupling mechanism,which is supported by theoretical calculations.The graphene can host unpaired spin electrons,leading to a short acquisition time for a solidstate nuclear magnetic resonance 13C spectrum from unlabeled graphene,which is ascribed to the very short spin-lattice relaxation time.High catalytic activity for transforming amine to imine with a conversion of>99%and a yield of∼97%is demonstrated,and high electronic conductivity of∼105 S·m^(−1) is found by terahertz spectroscopy.The reaction delivers a method for synthesizing graphene with a high spin concentration from perbrominated benzene molecules by using an active metallic agent,such as Na,Li,or Mg.
基金Supported by The National Natural Science Foundation of China
文摘The dynamics of a series of poly(n-alkyl methacrylates) is investigated by means of ^(13)C spin-lattice relaxation experiments. The results show that the dynamics has the polymer property dependence.
文摘The compatibility and dynamics of latex bidirectional/nterpenetrating polymer networks (LBIPNs) and latex IPN(LIPN) of poly(vinyl acetate)(PVAc) and poly (butyl acrylate )(PBA) are investigated by means of dynamic mechanical spectroscopy (DMS) and nuclear magnetic resonance (NMR) techniques. The results of DMS show that the compatibility of the LBIPNs is much better than that of the corresponding LIPN and depends to, a large extent on the distribution of PVAc both in the core and in the shell. The results of NMR measurements indicate that the rotational correlation times of the side- groups of PBA in the LBIPN are longer than those in the LIPN. The relation between the ^(13)C linewidths of PBA and temperature is also discussed.
基金This work was supported by National Key Project for Fundamental Research (N.95-11) and National Natural Science Foundation of Ch
文摘C spin-lattice relaxtion times for polystyrene nanolatex particles have been investigated. It was found that the dramatic increase at 80℃ annealing temperature is well below the Tg temperature of bulk polystyrene, the increase of relaxation time of aromatic carbons is larger than that of for aliphatic carbons at transition annealing temperature.
基金National Natural Science Foundation of China (No. 29671026)Natural Science Foundation of Zhejiang Province (No. 296062)State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics (No. 971502).
文摘Nine Ln( Ⅲ ) complexes with a novel Schiff base derived from diglycolamine and benzoylacetone (BZDA) have been synthesized and characterized. They can be formulated as [Ln2(BZDA)3(NO3)3](NO3)3· nH2O(Ln=La, Pr, Nd, Sm, n = 4; Ln=Gd, Tb, Er, Yb, Y, n = l). Enamic form mechanism in this β-diketone Schiff base and its complexes were suggested and proved by IR, UV and NMR methods. The 13C spin-lattice relaxation time T1 and the ratios of r(ci-Ln)/r(cj-Ln) were measured by a 500 MHz NMR instrument for elucidating the formation of the stable sk-membered chelate ring structure in these complexes. The EPR spectrum of the Gd( Ⅲ ) complex exhibits the 'U' spectral feature and 'zero field effect'. On the basis of them, the crystal field strength and the local symmetry around Gd3+ in the complex have been discussed.
文摘Fatty acids such as oleic and stearic acids having a long hydrocarbon chain are known to exist as dimers in their melt and even in a non-polar solvent. In their melt the dimers arrange longitudinally and alternately to form clusters which resemble a smectic liquid crystal. The clusters determine the liquid properties of the fatty acids such as density, viscosity and fluidity. Then, do the dimers of fatty acid having a moderate-length hydrocarbon chain construct such the clusters? In the present study the dynamic molecular behavior and assembly structure of octanoic acid in its melt and also in CCl4 solution have been investigated by the X-ray diffraction, near infrared spectroscopy, 1H-NMR chemical shift, self-diffusion coefficient and 13C-NMR spin-lattice relaxation time measurements. From these results it has been revealed that the clusters of octanoic acid exist in its melt and also in CCl4 and that the clusters in the melt disintegrate with an increase in temperature. The dissociation profile of dimers of octanoic acid into monomers in CCl4 also has been clarified.
基金supported by the National Natural Science Foundation of China(Grant Nos.11825403,and 11804138)the Program for Professor of Special Appointment(Eastern Scholar)+1 种基金supported by Anhui Provincial Natural Science Foundation(Grant No.1908085MA10)the Opening Foundation of State Key Laboratory of Surface Physics Fudan University(Grant No.KF2019_07)。
文摘Spin-lattice (SL) coupling plays an important role in spintronic applications given its effects on magnetic,ferroelectric,optical,and thermodynamic properties.Experiments and theoretical calculations have revealed a large SL coupling effect in CrGeTe_(3) and CrI_(3) monolayers.However,the microscopic origin of SL coupling in these systems is still unclear.In this work,we develop a systematic method to explore the atomistic mechanism of SL coupling based on the density functional theory.We find that the first-and second-order SL couplings in ternary system CrGeTe_(3) are considerably stronger than those in binary system CrI_(3).For the first-order SL coupling,the Cr ions of the magnetic pair and Ge ions positively contribute to the strain enhancement of ferromagnetism in CrGeTe_(3).However,the Cr ions provide a negative contribution in CrI_(3).Furthermore,our tight-binding analysis suggests that the p-d hopping in CrGeTe_(3) gradually decreases with the tensile strain,rapidly enhancing the ferromagnetism under the tensile strain.The large frequency shifts in CrGeTe_(3) are caused by the large second-order exchange derivatives (one type of second-order SL coupling) of the Cr ions of the magnetic pair.
基金Project supported by Beijing Natural Science Foundation,China(Grant No.JQ18014)the National Natural Science Foundation of China(Grant No.12074371)Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000),and CAS Interdisciplinary Innovation Team.
文摘Ultrathin van der Waals(vdW)magnets provide a possibility to access magnetic ordering in the two-dimensional(2D)limit,which are expected to be applied in the spintronic devices.Raman spectroscopy is a powerful characterization method to investigate the spin-related properties in 2D vdW magnets,including magnon and spin–lattice interaction,which are hardly accessible by other optical methods.In this paper,the recent progress of various magnetic properties in 2D vdW magnets studied by Raman spectroscopy is reviewed,including the magnetic transition,spin-wave,spin–lattice interaction,symmetry tuning induced by spin ordering,and nonreciprocal magneto-phonon Raman scattering.
文摘According to a uniform and simple method of calculating spin-lattice coupling coefficients and the pert1rbation formulas of gi factors and hyperfine structure constants Ai based on the cluster approach for 3d7 ions in cubic,tetragonal and trigonal octahedral crystal fields, the spin-lattice coupling coefficients Fij (F11, Fl2, F44), Zij (Z11, Z12,Z44) and also g factor and hyperfine constant A for MgO:Co2+ are calculated by using the parameters obtained from the optical spectra without adjustable parameters. The calculated results show good agreement with the observed values.The difiiculty in explaining the coeficients Fij and Zij is therefore removed.
基金financially supported by the National Natural Science Foundation of China(NSFC,Nos.21573235,U1632159 and 21875249)。
文摘A new 3 d transition-metal molybdate-tellurite(NH4)2 Co(TeMo2O9)2 was obtained through a conventional hydrothermal method.This compound was confirmed to crystallize in the monoclinic system of space group P2_(1)/c with a=10.5133(5),b=10.6456(5),c=7.6078(5)Å,β=108.879(6)o,V=805.66(8)Å^(3),Z=2,M_(r)=1021.97,Dc=4.213 g/cm^(3),μ=7.685 mm^(–1),F(000)=930,the final R=0.0399 and w R=0.1025 for 1580 observed reflections with I>2σ(I),showing a tunnel structure with spin triangle-lattice composed by CoO_(6) octahedra.Magnetic and heat capacity measurements confirmed a paramagnetic behavior down to 2 K with a negative Weiss temperature of–20 K,suggesting remarkable spin frustration in the system.
