Preparation And Thermoelectric Properties Of Sm³⁺ And Sr²⁺ Substituted CaMnO₃

Thermoelectric material is a kind of functional material converting heat energy directly to electric thermal energy and electrical.Devices made of thermoelectric material have many special advantages,and have been successfully used in a few acmes of science and technology.The thermoelectric phenomena,the history and the recent development progress of thermoelectric materials were reviewed in detailed at first.Oxide thermoelectric materials were found to have high working temperature,oxidation-resistant,no pollution, simple preparation,long life and have become new candidate materials with a potential to study and applying values.In my paper,Oxide CaMnO₃ has been selected as this study due to very good thermoelectric performance and its thermoelectric properties were investigated by different dopants.In this paper,Thermoelectric materials of pure CaMnO₃ and the CaMnO₃ with doping different ions(Sm³⁺,Sr²⁺) were synthesized by the sol-gel method and sintering at 1000℃in air.TG-DTA,IR,XRD,SEM and thermoelectric property test used to research the structure, microscopic appearance and thermoelectric properties(such as the Seebeck coefficient, electrical resistivity and power factor) of CaMnO₃.Doping different ions which effect on the structure of CaMnO₃ was also studied.The experimental results show that the sol-gel method is better than others,the samples have condensed microstructure and better thermoelectric properties.Doping each kind of different metallic ion according to the different allocated proportion(Sm³⁺,Sr²⁺),the power factor of material gets especially improvement.Sm³⁺optimized the sample's current carrier density,enable the thermoelectric performance to have very big degree improvement.