论文部分内容阅读
水热法合成铬酸镧及铬酸镧基材料的温度较低(比空气中合成低200～300℃)、反应简单、产物均匀,粒度均一(0.5～1μm)。合成产物均具有单斜畸变(β=90.35～90.38°)的钙钛矿型结构。在LaCrO_3中掺杂Ca~(2+)置换部分La~(3f),对提高电导率的效果较掺杂Mg~(2+)者为优。氧化气氛下制得的(La_(1-x)Ca_x)CrO_3表现为非本征电导特征;还原气氛下制得者为本征电导。本征电荷载流子是由激活过程产生,其激活能约为O.7leV。(La_(1-x)Ca_x)CrO_3为反铁磁体(Néel温度约288K),兼具有寄生铁磁性。
Hydrothermal synthesis of lanthanum chromite and lanthanum chromite based materials at a lower temperature (lower than air synthesis 200 ~ 300 ℃), the reaction is simple, uniform, uniform particle size (0.5 ~ 1μm). The synthesized products have perovskite structure with monoclinic distortion (β = 90.35 ~ 90.38 °). In LaCrO_3 doping Ca ~ (2 +) replacement part La ~ (3f), to improve the conductivity of the effect of doping Mg ~ (2+) is better. The (La_ (1-x) Ca_x) CrO_3 prepared under an oxidizing atmosphere showed an extrinsic conductance characteristic and the one obtained under a reducing atmosphere was an intrinsic one. Intrinsic charge carriers are generated by the activation process, the activation energy is about O. 7leV. (La_ (1-x) Ca_x) CrO_3 is an antiferromagnet (Néel temperature is about 288K) and possesses parasitic ferromagnetism.