Influence of sintering temperature on thermoelectric properties of La0.9Sr0.1FeO3 ceramics

摘要 利用传统的固相反应分别在1250℃，1300℃，1350℃.烧结条件下制备出钙钛矿结构的La0.9Sr0.1FeO3陶瓷样品.样品的XRD粉末衍射结果显示不同烧结温度的La0.9Sr0.1FeO3陶瓷样品都是单相的正交结构，同时晶胞体积随着烧结温度的升高而减小.从样品的SEM结果看出，随着烧结温度的升高，晶粒逐渐变大，并且晶粒间的空隙逐渐减小，样品更加致密.在室温到800℃的 关键词: 铁酸镧陶瓷 / 热电性能 / 烧结温度 Abstract Perovskite La0.9Sr0.1FeO3 ceramics have been synthesized at 1250℃，1300℃ and 1350℃ by the conventional solid-state reaction technique. From their crystal structures determined by powder X-ray diffraction，we found that the lattice volume decreases with increasing sintering temperature. The scanning electronic microscope (SEM) images of surface microstructures of the samples show that the average grain size increases with increasing sintering temperature. The electrical resistivity and Seebeck coefficient have been measured between room temperature and 800℃. At low temperatures，the electrical resistivity shows a semiconductivity-like behavior. With further increasing of temperature，the electrical resistivity slightly increases. An adiabatic hopping conduction mechanism of small-polarons is suggested from the temperature dependence of the electrical resistivity，which has different activation energies at low and high temperatures. The Seebeck coefficient rapidly decreases with increasing temperature，and reaches a saturation value about 600℃. With further increasing of temperature，the Seebeck coefficient slightly increases. With the increase of sintering temperature，the electrical resistivity decreases，while the Seebeck coefficient increases. Therefore，the power factor increases with increasing sintering temperature. The highest power factor of 90 μW/K2m was obtained at 727℃ for sample sintered at 1350℃. Keywords: LaFeO3 ceramics / thermoelectric properties / sintering temperature 作者及机构信息 王洪超, 王春雷, 苏文斌, 刘剑, 赵越, 彭华, 张家良, 赵明磊, 李吉超, 尹娜, 梅良模 1. 山东大学物理学院晶体材料国家重点实验室，济南 250100 基金项目: 国家重点基础研究发展计划(973)项目(批准号：2007CB607504）、国家自然科学基金(批准号：50572052）资助的课题. Authors and contacts Wang Hong-Chao, Wang Chun-Lei, Su Wen-Bin, Liu Jian, Zhao Yue, Peng Hua, Zhang Jia-Liang, Zhao Ming-Lei, Li Ji-Chao, Yin Na, Mei Liang-Mo 1. 山东大学物理学院晶体材料国家重点实验室，济南 250100 参考文献 [1] ［1］ Terasaki I，Sasago Y，Uchinokura K 1997 Phys. Rev. B 56 R12685 [2] ［2］ Chen X Y，Xu X F，Hu R X，Ren Z，Xu Z A，Cao G H 2007 Acta Phys.Sin. 56 1627 (in Chinese) ［陈晓阳、徐象繁、胡荣星、任之、许祝安、曹光旱 2007 物理学报 56 1627］ [3] ［3］Yu M, Yang H S, Ruan K Q, Li P C, Li H L, Chai Y S, Cao L Z 2002 Acta Phys. Sin. 51 663 (in Chinese) ［于旻、杨宏顺、阮可青、李鹏程、李慧玲、柴一晟、曹烈兆 2002 物理学报 51 663］ [4] ［4］ Okuda T，Nakanishi K，Miyasaka S，Tokura Y 2001 Phys. Rev. B 63 113104 [5] ［5］ Ohta S，Nomura T，Ohta H，Hirano M，Hosono H，Koumoto K 2005 Appl. Phys. Lett. 87 092108 [6] ［6］ He T，Chen J Z，Calvarese T G，Subramainan M A 2006 Solid State Sci. 8 467 [7] ［7］ Ullmann H，Trofimenko N，Stover F，Stver D，Ahmad-Khanlou A 2000 Solid State Ionics 138 79 [8] ［8］ Iwasaki K，Ito T，Yoshino M，Matsui T，Nagasaki T，Arita Y J 2006 J. Alloys Comp. 430 297 [9] ［9］ Jung W H 2001 Physica B 299 120 [10] ］ Kobayashi K，Yamaguchi S，Tsunoda T，Imai Y 2001 Solid State Ionics 144 123 [11] ］Jiang J, Li Y L, Xu G J, Cui P, Wu T, Chen L D, Wang G 2007 Acta Phys. Sin. 56 2858 (in Chinese) ［蒋俊、李亚丽、许高杰、崔平、吴汀、陈立东、王刚 2007 物理学报 56 2858］ [12] ］ Zhou X D，Wang J B，Thomsen E C 2006 J. Electrochem. Soc. 153 J133 [13] ］ Mott N F，Davis E A 1971 Electrical Process in Non-Crystal-line Materials (Oxford：Oxford Univ.) [14] ］ Jung W H，Iguchi E 1998 J. Phys. D：Appl. Phys. 31 794 [15] ］ Weber W J，Griffin C W，Bates J L 1987 J. Am. Ceram. Soc. 70 265 [16] ］ Wood C，Emin D 1984 Phys. Rev. B 29 4582 施引文献