Ca_(1-x)Sm_xMnO_3粉体的制备及其结构与导电性  

Preparation of Ca_(1-x)Sm_xMnO_3 powders and their structure and conductive properties

作　　者：孟宪伟[1] 郝素娥[1] 李佳龙[1] 

机构地区：[1]哈尔滨工业大学应用化学系,哈尔滨150001

出　　处：《材料科学与工艺》2011年第5期58-62,共5页Materials Science and Technology

基　　金：国家自然科学基金资助项目(20571020)

摘　　要：为了实现改性CaMnO3粉体在导电材料领域的应用,采用自蔓延溶胶-凝胶法合成了Ca1-xSmxMnO3(0≤x≤0.3)粉体,并研究了不同Sm掺杂量对Ca1-xSmxMnO3粉体结构和导电性的影响.结果表明,Sm掺杂能够有效降低CaMnO3粉体的室温电阻率,且随着Sm掺杂量的增大呈现典型的V型变化趋势,在x=0.2时电阻率最低,为0.2920Ω.m,且Ca0.8Sm0.2MnO3粉体具有较好的频率稳定性和高温导电性能.XRD和SEM结果表明,随x值增大Ca1-xSmxMnO3衍射峰的强度有所减小,并向小角度方向偏移;晶胞参数和晶胞体积逐渐增大;晶粒尺寸呈现先减小后增大的变化趋势.Sm掺杂能够引起Ca1-xSmxMnO3的晶格畸变,并由此导致了Ca1-xSmxMnO3粉体电阻率先降后升的变化规律.The modified Ca1-xSmxMnO3（0≤x≤0.3） powders were prepared through sol-gel auto-combustion route for their future application in conductive materials.The effects of Sm doping contents on the structure and conductive properties of the powders were studied.The results show that the doping of Sm can decrease the resistivity of CaMnO3 powders effectively and the resistivity of the modified powders represents the typical V type variation with the increase in the doping contents,and the Ca1-xSmxMnO3 powders with the lowest resistivity of 0.2920 Ω·m are obtained when the x=0.2.Meanwhile,the Ca0.8Sm0.2MnO3 powders have good frequency stability and good conductivity in high temperature.The XRD and SEM analyses illustrate that with the increase in x,the diffraction peaks of Ca1-xSmxMnO3 powders move to the small angles with the weakening in intensities,and the cell parameters as well as the cell volume is increased contemporaneously.The grain size is decreasing continuously when x is changing from 0 to 0.2,however,the grain size begins to increase slightly when x increases to 0.3.The distortion of crystal lattices caused by doping of Sm leads to the variation law of resistivity as ＂V＂ type of Ca1-xSmxMnO3 powders.

关 键 词：导电粉 CaMnO3 稀土 结构分析 

分 类 号：O614.23[理学—无机化学] O614.33[理学—化学]