La_(0.67)Pb_(0.33)Mn_(1-x)Ti_xO_3的结构、红外及磁学性质

Crystal Structure,Infrared and Magnetic Properties of La_(0.67)Pb_(0.33)Mn_(1-x)Ti_xO_3

采用空气中固相反应烧结法制备了一系列钙钛矿结构的掺杂稀土锰氧化物La0．67Pb0.33Mn1-xTixO3（x=0，0．02，0．05，0．1，0．15，0．2）多晶样品．X射线衍射（XRD）分析和扫描电镜（SEM）观测的结果表明掺杂Ti离子浓度越大，形成多晶样品的晶粒越大，未掺杂Ti离子的La0．67Pb0．33MnO3在所有的样品中晶粒最小．红外吸收光谱测量发现样品在601cm^-1～571cm^-1范围出现了吸收峰并且峰的位置随掺杂Ti离子浓度的增加而向高频方向偏移．样品的磁性质测量表明掺杂Ti离子的浓度对材料的磁电阻有明显影响．

A series of manganite perovskite polycrystalline samples of LaLa0.67Pb0.33Mn1-xTixO3（x= 0,0. 02,0. 05,0.1,0. 15,0.2） were prepared by solid state reaction in air. The XRD analyses and SEM image observation indicate the more concentration of the doped Ti ion is,the bigger of the crystal grain is. Compared to other doping samples, the size of undoped La0.67Pb0.33MnO3 crystal grains is least. The samples＇ infrared absorption spectra have been measured at room temperature and all samples appear the absorption peak in the range of 601cm^-1～571cm^-1. The peak moves from a lower frequency to a higher frequency along with the doping ion concentration increasing. Magnetic property survey of the samples indicates the concentration of doping Ti ions has an important effect on magnetoresistance （MR） of samples.