ELECTRICAL TRANSPORT IN RARE EARTH ORTHO CHROMITES, ORTHO MANGANITES AND ORTHO FERRITES
ELECTRICAL TRANSPORT IN RARE EARTH ORTHO CHROMITES, ORTHO MANGANITES AND ORTHO FERRITES
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DOI：
10.1016/0022-3697(71)90019-9
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发表时间：
1971-01-01
影响因子：
4
通讯作者：
RAO, CNR
中科院分区：
文献类型：
--
作者：
RAO, GVS;WANKLYN, BM;RAO, CNR
稀土正铬酸盐、锰氧化物和铁氧体为AREP型半导体，电导率在10−4-10−1欧姆−1 cm−1范围内。各系列钙钛矿的电导率随稀土原子序数的增加而降低。在三个系列的固体中，离子对电导率的贡献都很小。这些固体在∼1000°C以下都没有表现出本征行为。这些稀土化合物的导电行为反映了这些材料中已知的结晶学、介电和磁性转变。这些化合物中的塞贝克系数很大，这是窄带材料的典型特征；塞贝克系数在发生磁性和介电转变的温度下显示出显著的变化。这三个系列稀土化合物的电输运性质基本上是由过渡元素的电子控制的，表现出局域行为。这一结论与光谱结果和古德足够的预言是一致的。在所有这些化合物中，小极化子似乎负责传导。
Rare earth ortho-chromites, -manganites and -ferrites arep-type semiconductors with conductivities in the range 10−4–10−1ohm−1cm−1. The conductivity in each series of perovskites decreases with the increasing atomic number of the rare earth. The ionic contribution to conductivity is small in all the three series of solids. None of these solids exhibits intrinsic behavior up to ∼1000°C. The conductivity behaviors of these rare earth compounds reflect the known crystallographic, dielectric and magnetic transitions in these materials. Seebeck coefficients in these compounds are large, typical of narrow-band materials; the Seebeck coefficients show marked changes at temperatures where magnetic and dielectric transitions occur. The electrical transport properties of all the three series of rare earth compounds are essentially controlled by thed-electrons of the transition elements which show localized behavior. This conclusion is in agreement with the results from optical spectra and the predictions of Goodenough. In all these compounds small polarons seem to be responsible for the conduction.