| Sr和Co共掺杂对PrAlO3钙钛矿氧化物的结构和电性能的影响 |
| Effect of Strontium and Cobalt Co-doping on the Structural and Electrical Properties of PrAlO3 Perovskite Oxides |
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| 摘要: 采用柠檬酸盐法结合高温烧结制备了(Pr,Sr)(Al,Co)O3-δ系列钙钛矿氧化物导电陶瓷。使用X射线衍射(XRD)、扫描电镜(SEM)和直流四线法等手段对样品的物相、微观结构和电性能进行了表征。结果表明:所制备的Pr0.9Sr0.1Al1-yCoyO3-δ(y=0.1～0.5)陶瓷均为单相菱方钙钛矿结构,在掺杂范围内其晶胞体积、相对密度和电导率都随Co掺杂量y的增加而增大,但电导率的增幅在逐步减小;所有陶瓷样品在空气中都是氧离子与电子空穴的混合导体,电导行为符合小极化子跳跃机制。对于Pr1-xSrxAl0.5Co0.5O3-δ(x=0.1～0.4)陶瓷,当x=0.2时样品有较明显的第二相(Pr,Sr)CoO3析出,说明Sr在该体系的固溶限在10～20at%之间,而且随着x的进一步增加,(Pr,Sr)CoO3增多并成为主相;在测量温度范围内,Pr1-xSrxAl0.5Co0.5O3-δ的电导率随x的增加大体呈现出一个先增大后减小的变化趋势,在x=0.3附近达到一个最大值,当x≥0.2时还可观察到明显的半导体-金属性转变,且转变温度随x的增加而逐渐降低。 |
| 关键词: 共掺杂 PrAlO3 电性能 混合导体 半导体-金属转变 |
| 基金项目: 国家自然科学基金(No.11204108),江苏省高校自然科学基金(No.11KJB430006),江苏省普通高校研究生科研创新计划(No.CXLX11-0293) 资助项目。 |
| Abstract: Novel Sr- and Co-codoped (Pr,Sr)(Al,Co)O3-δ perovskite oxide conducting ceramics were prepared by citrate process combined with subsequent high-temperature sintering. The phase composition, microstructure and electrical properties of the obtained ceramics were characterized by XRD, SEM and direct current four-wire method. The experimental results show that all the as-prepared Pr0.9Sr0.1Al1-yCoyO3-δ(y=0.1～0.5) ceramics are a single-phase rhombohedral perovskite structure, and their unit cell volumes, relative densities and electrical conductivities increase with increasing y in the doping range, while the increasing rate in electrical conductivity progressively decrease. Furthermore, these samples are a mixed conductor of oxygen ion and hole in air and their electrical conductivities are absolutely dominated by p-type conduction. The temperature dependence of electrical conductivity for Pr0.9Sr0.1Al1-yCoyO3-δ can be described by the small polaron hopping mechanism. For the as-prepared Pr1-xSrxAl0.5Co0.5O3-δ(x=0.1～0.4) ceramics, a second phase (Pr,Sr)CoO3 obviously precipitates when x=0.2, indicating that the solid solubility limit of Sr on A site in this system is between 10at% and 20at%, and the (Pr, Sr)CoO3 phase in samples increases gradually and finally becomes the main phase with further increase in Sr content. It is found that the electrical conductivity of Pr1-xSrxAl0.5Co0.5O3-δ ceramics roughly exhibits a trend of first increase and then decrease with increasing x in the whole examined temperature range, and reaches the maximum value at around x=0.3. Additionally, the semiconductor-to-metal transition in the conduction behavior is obviously observed for the samples with x≥0.2, and the transition temperature gradually decreases with increasing Sr content. |
| Keywords: co-doping PrAlO3 electrical properties mixed conductor semiconductor-metal transition |
| 投稿时间：2012-12-25 修订日期：2013-01-31 |
| 摘要点击次数: 2320 |
| 全文下载次数: 2564 |
| 郭银涛,叶芹,向军,徐加焕.Sr和Co共掺杂对PrAlO3钙钛矿氧化物的结构和电性能的影响[J].无机化学学报,2013,29(5):958-964. |
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