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THE SYNTHESIS AND MAGNETOSTRICTION OF P rx Ce 1 x Fe 2 COMPOUNDS

Y.X.Li , G.Z.Xu , J.P.Qu , F.G.Liu and B.W.Wang Hebei University of Technology , Tianjin 300130 , China C.C.Tang.G.H.Wu and W.S.Zhan State Key Laboratory for Magnetism , Institute of Physics , CAS , Beijing 100080 , China C.Zhao Tianjin University , Tianjin 300072 , China S.X.Gao Hebei Normal University , Shijiazhuang 050091 , China

金属学报(英文版)

The synthesis and magnetic properties of Pr xCe 1 x Fe 2 have been investigated. The forma tion of Pr xCe 1 x Fe 2 is found to depend strongly on annealing temperature. Pure single phase compound can be synthesized at ambient pressure when x≤0 5. The main phase of the Laves structure can still be observed up to x=0 8. Magnetostriction increases with in creasing x and a largest saturation magnetostriction 200 ppm is observed for x=0.5.

关键词: magnetostriction , null , null

Li1+x(Fey/2Niy/2Mn1-y)1-xO2正极材料的合成及电化学性能

王秋艳 , 徐连义 , 付煜 , 张艳丽 , 谢嫚

稀有金属材料与工程

采用低温共沉淀-水热-煅烧法合成了锂离子电池Fe-Ni-Mn体系正极材料Li1+x(Fey/2Niy/2Mn1-y)1-xO2,并用XRD、SEM、ICP光谱和电化学性能测试对材料进行了表征.XRD测试和ICP分析表明,Fe、Ni取代Li2MnO3中的部分Mn,形成很好的固溶结构yLiFe1/2Ni1/2O2-(1-y)Li2MnO3 (y=0.l,0.2,0.3,0.4,0.5).SEM测试表明,取代量y不同,材料的表观形貌有所不同,y=0.4时材料的颗粒粒径均匀、较小,呈类球形结构.电化学性能测试表明,当y=0.4时,循环稳定性最好,充放电50次后放电比容量仍可维持在195.0 mAh/g,放电中值电压为3.5 V,y=0.4时样品在大倍率放电下的电化学性能表现良好.

关键词: 锂离子电池 , 正极材料 , Li1+x(Fey/2Niy/2Mn1-y)1-xO2 , 离子掺杂

Y3+,W6+掺杂的矿物锂快离子导体Li1.2+x-yYxTi1.9-xAl0.1Si0.1WyP2.9-yO12系统的合成与表征

张玉荣 , 陈宇

中国稀土学报

以LiTi2(PO4)3为母体,以天然高岭石为起始原料,经高温固相反应制得了一系列新的锂快离子导体Li1.2+x-yYxTi1.9-xAl0.1Si0.1WyP2.9-yO12(以下简称Y-W-Lisicon).X射线粉末衍射分析结果表明,在x=0.10,y≤0.20及x=0.20,y≤0.20的组成范围内能得到空间群为R3c,类似于Nasicon的三方结构,但在上述组成范围内均有杂相存在.应用交流阻抗技术测定电导率的结果表明,起始组成为x=0.10,y=0.10的样品在室温下具有较高的离子电导率,为1.65×10-5 S·cm-1;组成为x=0.20,y=0.10的样品在573 K时具有较高的离子电导率,为6.53×10-3 S·cm-1,该样品的分解电压为3.0 V.

关键词: 矿物锂快离子导体 , Y-W-Lisicon , 高岭石 , 稀土

Y3+, S6+掺杂的矿物锂快离子导体Li1.2+x-yYxTi1.9-xAl0.1Si0.1SyP2.9-yO12系统的合成与表征

陈宇 , 张玉荣

中国稀土学报

以LiTi2(PO4)3为母体,以天然高岭石为起始原料,经高温固相反应制得了一系列新的锂快离子导体Li1.2+x-yYxTi1.9-xAl0.1Si0.1SyP2.9-yO12(以下简称Y-S-Lisicon).X射线粉末衍射分析结果表明在x≤0.3,y<(0.2+x)的组成范围内均能得到类似于Nasicon三方结构的相,同时还存在其他杂相.应用交流阻抗技术测定电导率的结果表明起始组成为x=0.1,y=0.15的合成物电导率最高,其在室温下的电导率为2.93×10-5 S·cm-1,在673 K时可达3.62×10-2 S·cm-1,其在473~673 K间的活化能为37.19 kJ·mol-1,分解电压为3.0 V.

关键词: 矿物锂快离子导体 , Y-S-Lisicon , 高岭石 , 稀土

Li+掺杂对Y2SiO5∶Pr3+上转换发光性能影响

刘成 , 杨毅 , 韩正玉 , 武晓雅 , 翁景霞 , 林璐

中国稀土学报 doi:10.11785/S1000-4343.20130408

采用溶胶-凝胶法制备Li+掺杂改性的Y2SiO5:Pr3+上转换发光材料,考察了Li+掺杂对样品晶型及发光性能的影响.采用XRD,DSC-TGA,FS对所制备的材料进行表征,结果表明Li+掺入浓度在7%~ 8%(摩尔分数)之间会引起Y2SiO5晶体类型由X型转变为X2型,且Li+掺入后样品转晶型温度由950℃降至800℃;样品经800℃煅烧处理后以X1型Y2SiO5为主相,850℃煅烧处理后以X2型Y2SiO5为主相;Li+掺入同时会提高Y2SiO5:Pr3+材料的上转换发光强度,Li+最佳掺杂浓度为10%,对于双掺杂pr3+,Li+:Y2SiO5体系中pr3+最佳掺杂浓度为1.2%.

关键词: 溶胶-凝胶法 , 上转换 , 晶相转变 , 锂掺杂 , 稀土

锂快离子导体Li1+2x+2yAlxMgyTi2-x-ySixP3-xO12系统的研究

张玉荣 , 王文继

功能材料

以LiTi2(PO4)3为基以天然高岭石为起始原料,经高温固相反应(~900℃)制得了一系列新的锂快离子导体材料Li1+2x+ 2yAlxMgyTi2-x-ySixP3-xO1 2(以下简称Ti-Mg-Lisicon).系统的合成温度随xy值的增大而降低.应用交流阻抗技术测定的电导率数据结果表明x=0.1,y=0.1的合成物的室温电导率最好为1.01×10-4S/cm,而400℃时x=0.1,y=0.3的合成物的电导率最大,为2.53×10-2S/cm.XRD分析结果表明在x=0.1,y≤0.8;x=0.2,y≤0.6的组成范围内均能得到空间群为R3c的合成物.

关键词: 锂快离子导体 , Ti-Mg-Lisicon , 高岭石

Multiferroic phase diagram of Y partially substituted Dy(1-x)Y(x)MnO(3)

Applied Physics Letters

The effect of nonmagnetic Y partial substitution at the Dy site in Dy(1-x)Y(x)MnO(3) up to x=0.2 on magnetism, specific heat, and ferroelectricity is investigated, which resulted in a preliminary multiferroic phase diagram. It is revealed that the Y partial substitution suppresses the Dy-spin ordering point (T(Dy)) and ferroelectric ordering point (T(FE)) but enhances the Mn-spin ordering point (T(N)). The interaction between the spins of Dy and Mn is remarkably affected by Y substitution. The measured electrical polarization depends on the Y substitution in a complex way because the ferroelectricity is sensitive to the interaction between the spins of Dy and Mn. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3536506]

关键词: ferroelectricity;polarization

Li1+2x+yAlxNdyTi2-x-ySixP3-xO12系统的锂快离子导体研究

陈瑞福 , 王文继

无机材料学报

Li1+2x+yAlxNdyTi2-x-ySixP3-xO12 锂快离子导体(以下简称Al-Nd-Lisicon)可以用精选的天然高岭石Al4[Si4O10](OH)8为起始原料,经与Li2CO3、TiO2、NH4H2PO4进行高温(800~1000℃)固相反应约20h而制得.一个空间群属于R3c的固溶体导电相可在y=0.5,x0.3和y=1.0,x0.4的组成范围内发现.该相具有较好的电导性和较低的活化能.起始组成y=1.0,x=0.3的合成物具有最高的电导率,在400℃时;其电导率达到3.08×10-2S/cm,离子导电激活能为35.2kJ/mol.

关键词: 矿物快离子导体 , null , null

Mechanism of upconversion emission enhancement in Y(3)Al(5)O(12):Er(3+)/Li(+) powders

稀土学报(英文版)

Er(3+) and Li(+) codoped Y(3)Al(5)O(12) (YAG) powders were prepared for a systematic investigation of their upconversion emissions. X-ray diffraction (XRD), upconversion emission spectra, pump power dependence, FT-IR spectra and decay time were studied to characterize the samples. With Li+ doping, the upconversion emission intensity of Er(3+) doped YAG powders was obviously enhanced, accompanied with an increase in the ratio of green to red intensity. The enhancement of emission intensity could be attributed to two mechanisms: one was the distortion of local crystal field around Er(3+), and the other was the decrease in the amount of CO(3)(2-) and OH(-) groups. Our results revealed that the latter was the dominant mechanism of the upconversion intensity enhancement in the YAG:Er(3+)/Li(+) powders.

关键词: luminescence;optical materials and properties;sol-gel preparation;nanomaterials;rare earths;nanocrystals;nanophosphors;li+

锂快离子导体Li{1+2x+yAlxYbyTi2-x-ySixP3-xO12系统的研究

张玉荣 , 王文继

无机材料学报 doi:10.3321/j.issn:1000-324X.2001.01.019

以LiTi2(PO4)3为基以天然高岭石为起始原料,经高温固相反应(9501150C)制得了一系列锂快离子导体材料Li1+2x+yAlxYbyTi2-x-ySixP3-xO12(以下简称Al-Yb-Lisicon). 系统的合成温度随xy值的增大而降低. 应用交流阻抗技术测定的电导率数据结果表明y=0.3,x=0.1的合成物的电导率最好,400C时电导率达2.4510-2S/cm,200400C内的电导激活能为38.3kJ/mol. XRD分析结果表明在y=0.3,x0.4及y=0.5,x0.3的组成范围内均能得到空间群为R3c的合成物.

关键词: 锂快离子导体 , Al-Yb-Lisicon , 高岭石

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