The compound {[Cu(Hpht)(N_3)]·H_2O}_n (Hpht = hydrogen phthalate) is formedby chains of copper atoms bridged simultaneously by syn-syn carboxylato and end-on azido bridges.Taking into account the large Cu-O(1)-C(...The compound {[Cu(Hpht)(N_3)]·H_2O}_n (Hpht = hydrogen phthalate) is formedby chains of copper atoms bridged simultaneously by syn-syn carboxylato and end-on azido bridges.Taking into account the large Cu-O(1)-C(7) bond angle of the single carboxylato bridge (131°), orthe large Cu-N(11)-Cu bond angle of the azido bridge (111.9°), a moderately intrachainantiferromagnetic behavior should be expected for the compound. This paper is devoted to examiningthe apparently anomalous intrachain ferromagnetic behavior of {[Cu(Hpht)(N_3)]·H_2O}_n, using firstprinciples within the full potential linearized augmented plane wave (FP-LAPW) method. The totalenergy, the density of states (DOS), and the spin distributions are obtained. The atomic spindistribution has been analyzed as resulting from the interplay of electron delocalization and spinpolarization. The DOS reveals a surprisingly strong exchange interaction between the d type orbitalsof the copper and the π molecular orbitals of the two ligands.展开更多
Magnetism has revolutionized important technologies,and continues to bring forth new phenomena in emergent materials and reduced dimensions.Here,using first-principles calculations,we demonstrate that the already-synt...Magnetism has revolutionized important technologies,and continues to bring forth new phenomena in emergent materials and reduced dimensions.Here,using first-principles calculations,we demonstrate that the already-synthesized two-dimensional(2D)Ni-tetracyanoquinodimethane(Ni_(2)(TCNQ)_(2))lattice is a stable ferromagnetism material with multiple spin-polarized Dirac cones.The conical bands in proximity of the Fermi level can be tuned by external tensile strain and show the fourfold degenerate electronic states at the critical tensile strain of~2.35%,whose energy dispersion is consistent with 2D Cairo pentagonal lattice.In addition,spin-orbital coupling can open a band gap at the Dirac point of A,leading to topologically nontrivial electronic states characterized by the non-zero Chern number and the edge states of nanoribbon.Our results offer versatile platforms for the realization of massless spintronics with full-spin polarization in 2D Cairo pentagonal Ni_(2)(TCNQ)_(2) Lattice.展开更多
The characters of coupling between two doublet NO radicals linked through electron-rich rings have been studied. The results demonstrate that the molecules have triplet ground states, and ferromagnetic coupling exists...The characters of coupling between two doublet NO radicals linked through electron-rich rings have been studied. The results demonstrate that the molecules have triplet ground states, and ferromagnetic coupling exists in these molecules.展开更多
In this study, we observe a strong inverse magnetoelectric coupling in Fe52.5Co22.5B25.0/PZN-PT multiferroic heterostructure, which produces large electric field（E-field） tunability of microwave magnetic properties....In this study, we observe a strong inverse magnetoelectric coupling in Fe52.5Co22.5B25.0/PZN-PT multiferroic heterostructure, which produces large electric field（E-field） tunability of microwave magnetic properties. With the increase of the E-field from 0 to 8 kV/cm, the magnetic anisotropy field Heffis dramatically enhanced from 169 to 600 Oe, which further leads to a significant enhancement of ferromagnetic resonance frequency from 4.57 to 8.73 GHz under zero bias magnetic field, and a simultaneous decrease of the damping constant α from 0.021 to 0.0186. These features demonstrate that this multiferroic composite is a promising candidate for fabricating E-field tunable microwave components.展开更多
A Ni(Ⅱ)coordination complex 1 with a novel boron-oxamido radical ligand was synthesized and isolated.Reactions of 1 with N,N-dimethyl-4-pyridinamine(DMAP)and 4,4'-bpy resulted in 2 and 3,respectively,accompanied ...A Ni(Ⅱ)coordination complex 1 with a novel boron-oxamido radical ligand was synthesized and isolated.Reactions of 1 with N,N-dimethyl-4-pyridinamine(DMAP)and 4,4'-bpy resulted in 2 and 3,respectively,accompanied by the spin state transition from S=1/2 to S=3/2.Both 2 and 3 were isolated as stable crystals and characterized to feature an S=3/2 spin state,with the S=1 Ni(Ⅱ)atoms ferromagnetically coupled with the ligand-centred radicals,by SQUID measurement and EPR spectroscopy.Complex 3 represents the first example of one-dimensional magnetic chain constructed by S=3/2 Ni(Ⅱ)-radical units.展开更多
Concise chemistry leads to a family of heptanuclear Co^(Ⅱ)-clusters,[Co_(7)(N_(3))_(12)(CH_(3)CN)_(12)][Y_(2)(NO_(3))_(4)(piv)_(4)]·2CH_(3)CN(DC1)(pivH=pivalic acid),[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(0...Concise chemistry leads to a family of heptanuclear Co^(Ⅱ)-clusters,[Co_(7)(N_(3))_(12)(CH_(3)CN)_(12)][Y_(2)(NO_(3))_(4)(piv)_(4)]·2CH_(3)CN(DC1)(pivH=pivalic acid),[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(0.4)(Cl)_(1.6)]·4CH_(3)CN(DC2)and[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(2)]·4CH_(3)CN(DC3),in which the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology.The resulting clusters exhibit interesting structural transformations and thermodynamically-distinct steady states verified by theoretical calcula-tions.Magnetic studies reveal the first observation of zero-field SMM behaviour in disk-like heptanuclear Co^(Ⅱ)complexes.展开更多
The ground state spins coupled through electron-rich rings of bicarbenes and binitreneshave been studied at UHF/6-31G* level. The results demonstrate that ferromagnetic couplingexists in these molecules, and electron-...The ground state spins coupled through electron-rich rings of bicarbenes and binitreneshave been studied at UHF/6-31G* level. The results demonstrate that ferromagnetic couplingexists in these molecules, and electron-rich rings are the potential ferromagnetic coupling units.展开更多
Single-molecule magnets(SMMs)are a kind of nanosized magnetic materials that are capable of storing massive bytes of information.Strongly coupling the spin centers in a proper manner is a usual approach to promote the...Single-molecule magnets(SMMs)are a kind of nanosized magnetic materials that are capable of storing massive bytes of information.Strongly coupling the spin centers in a proper manner is a usual approach to promote the working temperature(or blocking temperature)for SMMs.Electron delocalized radicals have been widely employed to accomplish this job.Here,we show a new manner by using weak but multiple B–H^(δ-)···Dy^(3+)inverse hydrogen bonding(IHB)interactions to control the magnetic couplings in a series of dimeric dysprosiacaborane SMMs.This approach leads to a record high T_(B)^(100s)of 10 K among non-radical bridged dimeric SMMs,which is mainly ascribed to strong ferromagnetic coupling(4.38 cm^(-1))and the proper alignment of the magnetic principle axes of the adjacent dysprosium(Ⅲ)ions.In verifying by theoretical calculations,these results demonstrate that IHB interactions can be used to construct strong axial ferromagnetic coupling and enhancing magnetic blocking temperature for SMMs.展开更多
Six novel μ-oxamido heterobinuclear complexes, namely Cu(oxae)Ln(Me2bpy)2-(ClO4)3 (Ln=La, Nd, Gd, Tb, Ho, Er), where oxae denotes N, N'-bis(2-aminoethyl)oxamido dian-ion, Me2bpy is 4,4'-dimethyl-2,2'-bipy...Six novel μ-oxamido heterobinuclear complexes, namely Cu(oxae)Ln(Me2bpy)2-(ClO4)3 (Ln=La, Nd, Gd, Tb, Ho, Er), where oxae denotes N, N'-bis(2-aminoethyl)oxamido dian-ion, Me2bpy is 4,4'-dimethyl-2,2'-bipyridyl, have been synthesized and characterized by elemental analyses, IR, conductivity measurements and electronic spectra. The temperature dependence of the magnetic susceptibility of Cu(oxae)Gd(Me2bpy)2(ClO4)3 has been meaured over the range 4-300 K. The least-squares fit of the experimental susceptibilities yielded J - 1.87 cm-1.The observed Gd(Ⅲ)-Cu(Ⅱ) coupling is ferromagnetic. One plausible mechanism that can cause a ferromagnetic coupling between Gd(Ⅲ) and Cu(Ⅱ) is discussed in terms of spin-polarization.展开更多
Pseudo spin valves（SVs） exhibiting perpendicular magnetic anisotropy were prepared by magnetron sputtering. Magnetization measurements of the Co/Pt multilayers were performed to select the reference and free layers....Pseudo spin valves（SVs） exhibiting perpendicular magnetic anisotropy were prepared by magnetron sputtering. Magnetization measurements of the Co/Pt multilayers were performed to select the reference and free layers. The selection criteria are square magnetic hysteresis loops, weaker current shunting effect, and proper coercivity. The optimal reference layer and free layer are Pt（5.0 nm）/[Co（0.4 nm）/Pt（0.6 nm）]3/Co（0.4 nm）/Cu（3.0 nm）and Cu（3.0 nm）/[Co（0.4 nm）/Pt（1.5 nm）]4, respectively.The resulting pseudo SV exhibits two well-separated hysteresis loops when the field is applied perpendicular to the film plane. The minor hysteresis loop corresponding to the free layer shifts toward negative direction of the magnetic field axis, indicating ferromagnetic interlayer exchange coupling between the two magnetic layers. The coupling also enhances the coercivity（HC） of both layers. The perpendicular giant magnetoresistance（GMR） of 2.7 % is achieved with current in plane measurement. The GMR first increases when Pt seed layer is thickened, reaches a maximum of 3.0 % at 4 nm and then decreases with the further increase of thickness. But thicker Cu spacer layer always lowers the GMR of the SV.展开更多
Using Bu4N[Fe(Tp*)(CN)3]- (Tp* = hydrotris(3,5-dimethylpyrazol-l-yl)borate) as the building block to react with Cun and N-methylimidazole, we obtained a one-dimensional (1D) beterobimetallic cyano-bridged chain, [Fe(T...Using Bu4N[Fe(Tp*)(CN)3]- (Tp* = hydrotris(3,5-dimethylpyrazol-l-yl)borate) as the building block to react with Cun and N-methylimidazole, we obtained a one-dimensional (1D) beterobimetallic cyano-bridged chain, [Fe(Tp*)(CN)3]2Cu(N- methylimidazole)2.2H20 (1). The crystal structures and magnetic studies demonstrate that complex 1 exhibits slow relaxation of the magnetization due to strong intrachain ferromagnetic coupling and weak interchain interactions.展开更多
文摘The compound {[Cu(Hpht)(N_3)]·H_2O}_n (Hpht = hydrogen phthalate) is formedby chains of copper atoms bridged simultaneously by syn-syn carboxylato and end-on azido bridges.Taking into account the large Cu-O(1)-C(7) bond angle of the single carboxylato bridge (131°), orthe large Cu-N(11)-Cu bond angle of the azido bridge (111.9°), a moderately intrachainantiferromagnetic behavior should be expected for the compound. This paper is devoted to examiningthe apparently anomalous intrachain ferromagnetic behavior of {[Cu(Hpht)(N_3)]·H_2O}_n, using firstprinciples within the full potential linearized augmented plane wave (FP-LAPW) method. The totalenergy, the density of states (DOS), and the spin distributions are obtained. The atomic spindistribution has been analyzed as resulting from the interplay of electron delocalization and spinpolarization. The DOS reveals a surprisingly strong exchange interaction between the d type orbitalsof the copper and the π molecular orbitals of the two ligands.
基金A.W.greatly appreciates the National Natural Science Foundation of China(No.11904131)the Natural Science Foundation of Shandong Province(No.ZR2019BA006)+2 种基金M.Z.thanks the supports from the National Natural Science Foundation of China(No.11774201)the Taishan scholarship of Shandong Province.N.R.appreciates the National Natural Science Foundation of China(No.51972148)L.D.thanks the support from the National Natural Science Foundation of China(No.51802118).
文摘Magnetism has revolutionized important technologies,and continues to bring forth new phenomena in emergent materials and reduced dimensions.Here,using first-principles calculations,we demonstrate that the already-synthesized two-dimensional(2D)Ni-tetracyanoquinodimethane(Ni_(2)(TCNQ)_(2))lattice is a stable ferromagnetism material with multiple spin-polarized Dirac cones.The conical bands in proximity of the Fermi level can be tuned by external tensile strain and show the fourfold degenerate electronic states at the critical tensile strain of~2.35%,whose energy dispersion is consistent with 2D Cairo pentagonal lattice.In addition,spin-orbital coupling can open a band gap at the Dirac point of A,leading to topologically nontrivial electronic states characterized by the non-zero Chern number and the edge states of nanoribbon.Our results offer versatile platforms for the realization of massless spintronics with full-spin polarization in 2D Cairo pentagonal Ni_(2)(TCNQ)_(2) Lattice.
文摘The characters of coupling between two doublet NO radicals linked through electron-rich rings have been studied. The results demonstrate that the molecules have triplet ground states, and ferromagnetic coupling exists in these molecules.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674187)
文摘In this study, we observe a strong inverse magnetoelectric coupling in Fe52.5Co22.5B25.0/PZN-PT multiferroic heterostructure, which produces large electric field（E-field） tunability of microwave magnetic properties. With the increase of the E-field from 0 to 8 kV/cm, the magnetic anisotropy field Heffis dramatically enhanced from 169 to 600 Oe, which further leads to a significant enhancement of ferromagnetic resonance frequency from 4.57 to 8.73 GHz under zero bias magnetic field, and a simultaneous decrease of the damping constant α from 0.021 to 0.0186. These features demonstrate that this multiferroic composite is a promising candidate for fabricating E-field tunable microwave components.
基金the National Key R&D Program of China(Grant 2018YFA0306004)the National Natural Science Foundation of China(Grant 21525102)for financial support.
文摘A Ni(Ⅱ)coordination complex 1 with a novel boron-oxamido radical ligand was synthesized and isolated.Reactions of 1 with N,N-dimethyl-4-pyridinamine(DMAP)and 4,4'-bpy resulted in 2 and 3,respectively,accompanied by the spin state transition from S=1/2 to S=3/2.Both 2 and 3 were isolated as stable crystals and characterized to feature an S=3/2 spin state,with the S=1 Ni(Ⅱ)atoms ferromagnetically coupled with the ligand-centred radicals,by SQUID measurement and EPR spectroscopy.Complex 3 represents the first example of one-dimensional magnetic chain constructed by S=3/2 Ni(Ⅱ)-radical units.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.21863009,22063008)the Natural Science Foundation of Ningxia Province(Nos.2023AAC03014,2023AAC03227,2021AAC03136,2021BEB04062)+1 种基金the Young Top-notch Talent Cultivation Program of Ningxia Province,the Discipline Project of Ningxia(No.NXYLXK2017A04)the China Postdoctoral Science Foundation(No.2022M723148).
文摘Concise chemistry leads to a family of heptanuclear Co^(Ⅱ)-clusters,[Co_(7)(N_(3))_(12)(CH_(3)CN)_(12)][Y_(2)(NO_(3))_(4)(piv)_(4)]·2CH_(3)CN(DC1)(pivH=pivalic acid),[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(0.4)(Cl)_(1.6)]·4CH_(3)CN(DC2)and[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(2)]·4CH_(3)CN(DC3),in which the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology.The resulting clusters exhibit interesting structural transformations and thermodynamically-distinct steady states verified by theoretical calcula-tions.Magnetic studies reveal the first observation of zero-field SMM behaviour in disk-like heptanuclear Co^(Ⅱ)complexes.
文摘The ground state spins coupled through electron-rich rings of bicarbenes and binitreneshave been studied at UHF/6-31G* level. The results demonstrate that ferromagnetic couplingexists in these molecules, and electron-rich rings are the potential ferromagnetic coupling units.
基金supported by the National Natural Science Foundation of China(22375157)the State Key Laboratory of Electrical Insulation and Power Equipment(EIPE23402,EIPE23405)+3 种基金the Special Support Plan of Shaanxi Province for Young Top-notch Talentthe Fundamental Research Funds for Central Universities(xtr052023002,xzy012023024)the China Postdoctoral Science Foundation(2023M742783,GZB20240599)the Shaanxi Postdoctoral Science Foundation(2023BSHYDZZ12)。
文摘Single-molecule magnets(SMMs)are a kind of nanosized magnetic materials that are capable of storing massive bytes of information.Strongly coupling the spin centers in a proper manner is a usual approach to promote the working temperature(or blocking temperature)for SMMs.Electron delocalized radicals have been widely employed to accomplish this job.Here,we show a new manner by using weak but multiple B–H^(δ-)···Dy^(3+)inverse hydrogen bonding(IHB)interactions to control the magnetic couplings in a series of dimeric dysprosiacaborane SMMs.This approach leads to a record high T_(B)^(100s)of 10 K among non-radical bridged dimeric SMMs,which is mainly ascribed to strong ferromagnetic coupling(4.38 cm^(-1))and the proper alignment of the magnetic principle axes of the adjacent dysprosium(Ⅲ)ions.In verifying by theoretical calculations,these results demonstrate that IHB interactions can be used to construct strong axial ferromagnetic coupling and enhancing magnetic blocking temperature for SMMs.
基金Project supported by the National Natural Science Foundation of China.
文摘Six novel μ-oxamido heterobinuclear complexes, namely Cu(oxae)Ln(Me2bpy)2-(ClO4)3 (Ln=La, Nd, Gd, Tb, Ho, Er), where oxae denotes N, N'-bis(2-aminoethyl)oxamido dian-ion, Me2bpy is 4,4'-dimethyl-2,2'-bipyridyl, have been synthesized and characterized by elemental analyses, IR, conductivity measurements and electronic spectra. The temperature dependence of the magnetic susceptibility of Cu(oxae)Gd(Me2bpy)2(ClO4)3 has been meaured over the range 4-300 K. The least-squares fit of the experimental susceptibilities yielded J - 1.87 cm-1.The observed Gd(Ⅲ)-Cu(Ⅱ) coupling is ferromagnetic. One plausible mechanism that can cause a ferromagnetic coupling between Gd(Ⅲ) and Cu(Ⅱ) is discussed in terms of spin-polarization.
基金financially supported by the National Natural Science Foundation of China (Nos. 11174020, 51331002, and 51371027)the Fundamental Research Funds for the Central Universities FRF-SD-12-011A
文摘Pseudo spin valves（SVs） exhibiting perpendicular magnetic anisotropy were prepared by magnetron sputtering. Magnetization measurements of the Co/Pt multilayers were performed to select the reference and free layers. The selection criteria are square magnetic hysteresis loops, weaker current shunting effect, and proper coercivity. The optimal reference layer and free layer are Pt（5.0 nm）/[Co（0.4 nm）/Pt（0.6 nm）]3/Co（0.4 nm）/Cu（3.0 nm）and Cu（3.0 nm）/[Co（0.4 nm）/Pt（1.5 nm）]4, respectively.The resulting pseudo SV exhibits two well-separated hysteresis loops when the field is applied perpendicular to the film plane. The minor hysteresis loop corresponding to the free layer shifts toward negative direction of the magnetic field axis, indicating ferromagnetic interlayer exchange coupling between the two magnetic layers. The coupling also enhances the coercivity（HC） of both layers. The perpendicular giant magnetoresistance（GMR） of 2.7 % is achieved with current in plane measurement. The GMR first increases when Pt seed layer is thickened, reaches a maximum of 3.0 % at 4 nm and then decreases with the further increase of thickness. But thicker Cu spacer layer always lowers the GMR of the SV.
基金financial support from the National Natural Science Foundation of China (21101021, 91122031)
文摘Using Bu4N[Fe(Tp*)(CN)3]- (Tp* = hydrotris(3,5-dimethylpyrazol-l-yl)borate) as the building block to react with Cun and N-methylimidazole, we obtained a one-dimensional (1D) beterobimetallic cyano-bridged chain, [Fe(Tp*)(CN)3]2Cu(N- methylimidazole)2.2H20 (1). The crystal structures and magnetic studies demonstrate that complex 1 exhibits slow relaxation of the magnetization due to strong intrachain ferromagnetic coupling and weak interchain interactions.
