A tetranuclear Ln(Ⅲ)-based complex:[Dy_(4)(dbm)_(4)(L)_(6)(μ_(3)-OH)_(2)]·CH_(3)CN(1)(HL=5-[(4-methylbenzylidene)amino]quinolin-8-ol,Hdbm=dibenzoylmethane)was manufactured and its structure was characterized in...A tetranuclear Ln(Ⅲ)-based complex:[Dy_(4)(dbm)_(4)(L)_(6)(μ_(3)-OH)_(2)]·CH_(3)CN(1)(HL=5-[(4-methylbenzylidene)amino]quinolin-8-ol,Hdbm=dibenzoylmethane)was manufactured and its structure was characterized in detail.Xray diffraction analysis shows that complex 1 belongs to the monoclinic crystal system and its space group is P2_1/n,which contains a rhombic Dy_(4)core.Magnetic measurements of 1 suggest it possesses extraordinary single-molecule magnet(SMM)behavior.Its energy barrier U_(eff)/k_(B)was 116.7 K,and the pre-exponential coefficient τ_(0)=1.05×10~(-8)s.CCDC:2359322.展开更多
This study investigates the physical properties of the rare earth XFes(X=Sm,Dy,or Nd)materials.Our analysis encompasses these compounds'structural,electronic,thermodynamic,and optical characteristics using density...This study investigates the physical properties of the rare earth XFes(X=Sm,Dy,or Nd)materials.Our analysis encompasses these compounds'structural,electronic,thermodynamic,and optical characteristics using density functional theory(DFT)as implemented in the Wien2k software package.The GGA+SOC+U method was employed to determine the exchange-correlation potential.Our results show that the XFes materials exhibit metallic behavior and exhibit ferromagnetic(FM)phases.Notably,our optical analysis reveals a strong absorption response in the UV region,with characteristic absorption curves and peak intensities varying across the different materials.We also investigated the thermodynamic properties of the materials,finding that the entropy increases exponentially with temperature as the materials transition from a ground state to a more disordered and amorphous state.Our thermodynamic results show that the Debye temperature decreases for all three materials,with DyFes exhibiting the highest Debye temperature at 0 K(307 K),followed by NdFes(298 K),and then SmFes(288 K).This indicates that each material has a unique thermal energy barrier to overcome before vibrations occur.As the temperature increases,the Debye temperature decreases,reflecting a decrease in the thermal energy required to induce vibrations.The differences in Debye temperature values between the three materials may suggest differences in their lattice structures or phonon properties,highlighting the importance of understanding these thermal properties for developing new materials and technologies.展开更多
The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evi...The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evidently,a vital prerequisite for practical applications is the exploration of candidate materials with prominent magnetocaloric performances.In this paper,the polycrystalline garnet RE_(3)Al_(5)O_(12)(RE=Tb,Dy and Ho)compounds with the cubic structure(space group:Ia3d)were prepared using the Pechini sol-gel method,and their crystal structure,magnetic properties and comprehensive magnetocaloric performances were studied.The analysis of magnetic susceptibility curves in a static magnetic field H=0.1 T reveal that the Dy_(3)Al_(5)O_(12)undergoes antiferromagnetic transition with Néel temperature TN≈2.6 K,whereas the Tb_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)exhibit no features indicative of the magnetic ordering processes down to 1.8 K.The comprehensive magnetocaloric performances,namely the maximum magnetic entropy change and relative cooling power,are derived indirectly from the isothermal field-dependent magnetization data,which yield 11.72,10.42,7.53 J/(kg·K)and 84.56,69.52,70.35 J/kg for the Tb_(3)Al_(5)O_(12),Dy_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)under a low field change(ΔH)of 0-2 T,respectively.The superior comprehensive magnetocaloric performances and wide operating temperature range of these compounds under lowΔH make them attractive for cryogenic MR technology.展开更多
文摘A tetranuclear Ln(Ⅲ)-based complex:[Dy_(4)(dbm)_(4)(L)_(6)(μ_(3)-OH)_(2)]·CH_(3)CN(1)(HL=5-[(4-methylbenzylidene)amino]quinolin-8-ol,Hdbm=dibenzoylmethane)was manufactured and its structure was characterized in detail.Xray diffraction analysis shows that complex 1 belongs to the monoclinic crystal system and its space group is P2_1/n,which contains a rhombic Dy_(4)core.Magnetic measurements of 1 suggest it possesses extraordinary single-molecule magnet(SMM)behavior.Its energy barrier U_(eff)/k_(B)was 116.7 K,and the pre-exponential coefficient τ_(0)=1.05×10~(-8)s.CCDC:2359322.
文摘This study investigates the physical properties of the rare earth XFes(X=Sm,Dy,or Nd)materials.Our analysis encompasses these compounds'structural,electronic,thermodynamic,and optical characteristics using density functional theory(DFT)as implemented in the Wien2k software package.The GGA+SOC+U method was employed to determine the exchange-correlation potential.Our results show that the XFes materials exhibit metallic behavior and exhibit ferromagnetic(FM)phases.Notably,our optical analysis reveals a strong absorption response in the UV region,with characteristic absorption curves and peak intensities varying across the different materials.We also investigated the thermodynamic properties of the materials,finding that the entropy increases exponentially with temperature as the materials transition from a ground state to a more disordered and amorphous state.Our thermodynamic results show that the Debye temperature decreases for all three materials,with DyFes exhibiting the highest Debye temperature at 0 K(307 K),followed by NdFes(298 K),and then SmFes(288 K).This indicates that each material has a unique thermal energy barrier to overcome before vibrations occur.As the temperature increases,the Debye temperature decreases,reflecting a decrease in the thermal energy required to induce vibrations.The differences in Debye temperature values between the three materials may suggest differences in their lattice structures or phonon properties,highlighting the importance of understanding these thermal properties for developing new materials and technologies.
基金supported by the National Natural Science Foundation of China(52301240,52472274)the Fundamental Research Funds for the Provincial Universities of Zhejiang(GK259909299001-022)。
文摘The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evidently,a vital prerequisite for practical applications is the exploration of candidate materials with prominent magnetocaloric performances.In this paper,the polycrystalline garnet RE_(3)Al_(5)O_(12)(RE=Tb,Dy and Ho)compounds with the cubic structure(space group:Ia3d)were prepared using the Pechini sol-gel method,and their crystal structure,magnetic properties and comprehensive magnetocaloric performances were studied.The analysis of magnetic susceptibility curves in a static magnetic field H=0.1 T reveal that the Dy_(3)Al_(5)O_(12)undergoes antiferromagnetic transition with Néel temperature TN≈2.6 K,whereas the Tb_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)exhibit no features indicative of the magnetic ordering processes down to 1.8 K.The comprehensive magnetocaloric performances,namely the maximum magnetic entropy change and relative cooling power,are derived indirectly from the isothermal field-dependent magnetization data,which yield 11.72,10.42,7.53 J/(kg·K)and 84.56,69.52,70.35 J/kg for the Tb_(3)Al_(5)O_(12),Dy_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)under a low field change(ΔH)of 0-2 T,respectively.The superior comprehensive magnetocaloric performances and wide operating temperature range of these compounds under lowΔH make them attractive for cryogenic MR technology.
