STRUCTURE AND ELECTRICAL-PROPERTIES OF LA1-XSRXCO1-YFEYO3 .1. THE SYSTEM LA0.8SR0.2CO1-YFEYO3
STRUCTURE AND ELECTRICAL-PROPERTIES OF LA1-XSRXCO1-YFEYO3 .1. THE SYSTEM LA0.8SR0.2CO1-YFEYO3
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DOI：
10.1016/0167-2738(94)00244-m
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发表时间：
1995-03-01
影响因子：
3.2
通讯作者：
SEHLIN, SR
中科院分区：
文献类型：
--
作者：
TAI, LW;NASRALLAH, MM;SEHLIN, SR
研究了La_（0.8）Sr_（0.2）Co_（1-y）Fe_yO_3（0 ≤ y ≤ 1）体系的晶体结构、热膨胀、热重、热电性和电导率随Co/Fe比和温度的变化。其导电机制是由于p型小极化子的绝热跳跃。在高温下，缺氧会导致晶格膨胀和电导率降低。所观察到的温度依赖性的塞贝克系数是由于在载流子浓度的变化所引起的热激发的电荷co 3+离子和诱导的氧空位的离子补偿。测量的电导率和塞贝克系数作为Co/Fe比的函数解释使用两个站点跳跃和网站渗流模型。这表明，在该系统中可能会发生一个优先的电子补偿的Fe离子Co离子。
Crystal structure, thermal expansion, thermogravimetry, thermoelectricity, and electrical conductivity of compositions in the system La0.8Sr0.2Co1-yFeyO3 with 0 less than or equal to y less than or equal to 1 were studied as function of Co/Fe ratio and temperature,:in air. The electrical conduction mechanism is attributed to the adiabatic-hopping of p-type small polarons. At high temperatures, oxygen deficiency causes lattice expansion and a reduction in electrical conductivity. The observed temperature dependence of the Seebeck coefficient is attributed to changes in carrier concentration caused by a thermally excited charge disproportionation of Co3+ ions and by the ionic compensation of induced oxygen vacancies. The measured electrical conductivity and Seebeck coefficient as a function of the Co/Fe ratio is interpreted using a two-site hopping and the site-percolation model. It is suggested that a preferential electronic compensation of Fe ions over Co ions may occur in this system.