Structure, magnetic properties, and thermal stability of ternary Sm1-xTmxCo5 compounds were studied via X-ray diffraction（XRD）, thermal magnetic analysis（TMA）, and magnetic measurements. XRD results show that all ...Structure, magnetic properties, and thermal stability of ternary Sm1-xTmxCo5 compounds were studied via X-ray diffraction（XRD）, thermal magnetic analysis（TMA）, and magnetic measurements. XRD results show that all the compounds have a main phase of hexagonal CaCu5-type crystal structure with small amount of impurity phases; increasing Tm content is associated with contraction of the hexagonal unit cell in the direction of the c axis and expansion of the a and b parameters. TMA results indicate that the Curie temperature（TC） of Sm1-xTmxCo5 compounds gets higher with the increase in Tm content.Magnetic measurements show that both the magnetic anisotropy field（HA） and the magnetization at an applied field of 7 T（M7 T） decrease with the increase of Tm content. However, the thermal stability of both the HAand M7 Tof all the Tm doped compounds is remarkably improved compared with that of the pure SmCo5 compound, leading to the result that both the M7 Tand HAof Sm0.8Tm0.2Co5 .2are higher than those of SmCo5 compound at 473 K, which indicates the good potential of Tm doped compound in the practical applications at elevated temperature.展开更多
Reactions of lanthanoid trichlorides with sodium cyclopentylcyclopentadienyl in THF afford bis(cyclopentylcyclopentadienyl) lanthanoid chloride complexes (C_5H_9C_5H_4)_2LnCl(THF)_n (Ln= Nd, Sm, n=1; Ln= Er, Yb, n= 0)...Reactions of lanthanoid trichlorides with sodium cyclopentylcyclopentadienyl in THF afford bis(cyclopentylcyclopentadienyl) lanthanoid chloride complexes (C_5H_9C_5H_4)_2LnCl(THF)_n (Ln= Nd, Sm, n=1; Ln= Er, Yb, n= 0). The compound [CP'_2SmCl(THF)]_2 (2) (Cp' =cyclopentylcy- clopentadienyl) crystallizes from mixed solvent of hexane and THF in monoclinic space group P_2_1/c with a = 11.583 (3), b = 23.019(6), c = 8.227 (2)(?), β= 90.26 (2)°, V= 2194 (1)(?)~3, D_c= 1.59 g/cm^3. μ= 28.6 cm^(-1), F(000) = 1060, Z= 2 (dimers). Its crystal molecule is a dimer with a crystallographic symmetry center. The central metal atom Sm is coordinated to two Cp' rings, two bridging chlorine atoms and one THF forming a distorted trigonal bipyramid. The crystal of [Cp'_2ErCl]_2 (3) belongs to the triclinic space group P(?) with a = 11.264 (2), b= 13.296(5), c = 14.296(6)(?), a = 96.99 (3), β= 112.47(2), γ= 102.78(2)°, V= 1865(1)(?)~3, D_c= 1.67 g /cm^3, μ= 48.0 cm^(-1), F(000) = 924, Z = 2 (dimers). The molecule is a dimer consisting of two Cp'_2 ErCl species bridged by two Cl atoms. The central metal atom Er is coordinated to two Cp' rings and two bridging chlorine atoms forming a pseudo- tetrahedron. All these complexes are soluble in THF, DME, Et_2O, toluene and hexane.展开更多
基金financially supported by the State Key Development Program of Basic Research of China (No. 2010CB934600)State Key Laboratory of Advanced Metals and Materials (No. 2011-ZD02)the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality (No. 009000543113507)
文摘Structure, magnetic properties, and thermal stability of ternary Sm1-xTmxCo5 compounds were studied via X-ray diffraction（XRD）, thermal magnetic analysis（TMA）, and magnetic measurements. XRD results show that all the compounds have a main phase of hexagonal CaCu5-type crystal structure with small amount of impurity phases; increasing Tm content is associated with contraction of the hexagonal unit cell in the direction of the c axis and expansion of the a and b parameters. TMA results indicate that the Curie temperature（TC） of Sm1-xTmxCo5 compounds gets higher with the increase in Tm content.Magnetic measurements show that both the magnetic anisotropy field（HA） and the magnetization at an applied field of 7 T（M7 T） decrease with the increase of Tm content. However, the thermal stability of both the HAand M7 Tof all the Tm doped compounds is remarkably improved compared with that of the pure SmCo5 compound, leading to the result that both the M7 Tand HAof Sm0.8Tm0.2Co5 .2are higher than those of SmCo5 compound at 473 K, which indicates the good potential of Tm doped compound in the practical applications at elevated temperature.
文摘Reactions of lanthanoid trichlorides with sodium cyclopentylcyclopentadienyl in THF afford bis(cyclopentylcyclopentadienyl) lanthanoid chloride complexes (C_5H_9C_5H_4)_2LnCl(THF)_n (Ln= Nd, Sm, n=1; Ln= Er, Yb, n= 0). The compound [CP'_2SmCl(THF)]_2 (2) (Cp' =cyclopentylcy- clopentadienyl) crystallizes from mixed solvent of hexane and THF in monoclinic space group P_2_1/c with a = 11.583 (3), b = 23.019(6), c = 8.227 (2)(?), β= 90.26 (2)°, V= 2194 (1)(?)~3, D_c= 1.59 g/cm^3. μ= 28.6 cm^(-1), F(000) = 1060, Z= 2 (dimers). Its crystal molecule is a dimer with a crystallographic symmetry center. The central metal atom Sm is coordinated to two Cp' rings, two bridging chlorine atoms and one THF forming a distorted trigonal bipyramid. The crystal of [Cp'_2ErCl]_2 (3) belongs to the triclinic space group P(?) with a = 11.264 (2), b= 13.296(5), c = 14.296(6)(?), a = 96.99 (3), β= 112.47(2), γ= 102.78(2)°, V= 1865(1)(?)~3, D_c= 1.67 g /cm^3, μ= 48.0 cm^(-1), F(000) = 924, Z = 2 (dimers). The molecule is a dimer consisting of two Cp'_2 ErCl species bridged by two Cl atoms. The central metal atom Er is coordinated to two Cp' rings and two bridging chlorine atoms forming a pseudo- tetrahedron. All these complexes are soluble in THF, DME, Et_2O, toluene and hexane.
