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测定了(La_(1-x)Ca_x)CrO_3材料(x=0～0.50)的温差电动势率及其在不同气氛下烧结后的电导率等参数。通过分析和计算,讨论了材料的电导机理。氧化气氛下制备的(La_(1-x)Ca_x)CrO_3表现为非本征电导,载流子浓度由其非化学计量的程度决定。化学计量的(La(1-x)Ca_x)CrO_(3-x╱2)表现为本征电导,载流子的产生借助于2Cr~(3+)=cr~(4+)Cr~(2+)的本征激活过程,激活能约为0.71eV。(La_(1-x)Ca_x)CrO_3材料中载流子的输运特性和掺杂的Ca~(2+)量有关,当x≤0.2时,可看成是小极化子的眺动电导;当x=0.50时,可能是一种小极化子和准自由电子的混合电导。
The parameters of the temperature difference electromotive force (La_ (1-x) Ca_x) CrO_3 (x = 0 ~ 0.50) and its conductivity after sintering under different atmospheres were measured. Through the analysis and calculation, the conductivity mechanism of the material is discussed. The (La_ (1-x) Ca_x) CrO_3 prepared under an oxidizing atmosphere exhibits extrinsic conductance and the carrier concentration is determined by its non-stoichiometry. The stoichiometry of (La (1-x) Ca_x) CrO_ (3-x / 2) appears as an intrinsic conductance and the generation of charge carriers is controlled by means of 2Cr ~ (3 +) = cr ~ (4 +) Cr ~ +), The activation energy is about 0.71eV. (La_ (1-x) Ca_x) CrO_3 is related to the amount of Ca 2+ doped. When x≤0.2, it can be regarded as the electric conductance of the small polaron ; When x = 0.50, it may be a mixture of small polarons and quasi-free electrons.