La_(0.9)Sr_(0.1)Ga_(0.8-x)Co_xMg_(0.2)O_(3-δ)(x=0,0.05,0.08)的结构和导电性

Crystal Structure and Electrical Conductivity of La_(0.9)Sr_(0.1)Ga_(0.8-x)Co_xMg_(0.2)O_(3-δ)(x=0,0.05,0.08)

用固相反应法合成了La0.9Sr0.1Ga0.8-xCoxMg0.2O3-δ(x=0,0.05,0.08))。XRD数据的Rietveld法精修表明其为体心正交结构,空间群Imma。掺Co量增大时,正交晶胞的晶格常数线性降低。采用直流四电极法和Hebb-Wagner极化法测定了总电导率和电子电导率。结果表明,氧离子电导率和总电导率随掺Co量增加而增大;掺Co可降低电导活化能,La0.9Sr0.1Ga0.8-xCoxMg0.2O3-δ对应x=0,0.05,0.08的活化能分别为0.978,0.739,0.489 eV。掺Co量达到0.08时,氧离子迁移数降为0.8。

La0.9Sr0.1Ga0.8-xCoxMg0.2O3-δ（x=0,0.05,0.08）were synthesized using conventional solid-state reaction technique. Rietveld refinement of powder X-ray diffraction data indicated that they belonged to body-centered orthorhombic system with space group Imrna. With the amount of doped cobalt increasing, a, b and c axis decreased lin- early. The total electrical conductivities of these compounds were measured by the method of D.C. four probes, and meanwhile electronic conductivities were measured using Hebb-Wagner polarization technique. The ionic electrical conductivity of oxygen and total electrical conductivity increased with the content of doped cobalt increasing. Doping cobalt can decrease the activation energy of conduction, of which values for La0.9Sr0.1Ga0.8-xCoxMg0.2O3-δ corresponding to x=0, 0. 05, 0. 08 are 0. 978, 0. 739 and 0. 489 eV respectively. Whereas the transference number of oxygen ion ofLa0.9Sr0.1Ga0.8-xCoxMg0.2O3-δ declined to 0. 8,when amount of doped cobalt inclined up to 0.08. Key words, perovskites; crystal structure; electrical properties