• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Diffusion and Defect Data. Solid State Data, Part B. Solid State Phenomena >Anomalous Thermal Behaviour of Mixed Cobaltites-Ferrites and Cobaltites-Chromites
【24h】

Anomalous Thermal Behaviour of Mixed Cobaltites-Ferrites and Cobaltites-Chromites

机译：混合钴铁素体和钴铁体-铬铁矿的异常热行为

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Series of the mixed cobaltites-ferrites RCo_(1-x)Fe_xO_3 (x = 0.1-0.9) and cobaltites-chromites RCo_(0.5)Cr_(0.5)O_3 (R = Pr,-Nd, Sm,Eu,Gd, Tb, Dy, Er) with the orthorhombic perovskite structure (space group Pbnm) have been prepared from stoichiometric amounts of rare earth oxides, Co_3O_4, Fe_2O_3 and Cr_2O_3 by solid-state reaction in air at 1473-1573 K. In situ high-temperature X-ray synchrotron powder diffraction revealed anomalous lattice expansion of both series, which is reflected in a sigmoidal dependence of the unit cell parameters and in abnormal anisotropic increase of the thermal expansion coefficients (TEC). Depending on the composition, several broad maxima in the temperature range of 500-1000 K are observed, which are evidently connected with the transitions of Co~(3+) cations to the higher spin states. The observed anomalies in the mixed cobaltites- ferrites and cobaltites-chromites are less pronounced compared with the corresponding "pure" cobaltites.
机译：混合的钴铁氧体RCo_（1-x）Fe_xO_3（x = 0.1-0.9）和钴-铬铁矿RCo_（0.5）Cr_（0.5）O_3（R = Pr，-Nd，Sm，Eu，Gd，Tb，通过化学计量的稀土氧化物Co_3O_4，Fe_2O_3和Cr_2O_3在空气中以1473-1573 K的固相反应制备了具有正交晶系钙钛矿结构（空间群Pbnm）的Dy，Er）。原位高温X-射线同步加速器粉末衍射揭示了两个系列的异常晶格膨胀，这反映为晶胞参数的S形依存关系和热膨胀系数（TEC）的异常各向异性增加。根据组成，观察到在500-1000 K的温度范围内有几个宽的最大值，这显然与Co〜（3+）阳离子向更高自旋态的跃迁有关。与相应的“纯”钴矿相比，在混合的钴铁矿-铁酸盐和钴-铬铁矿中观察到的异常现象不那么明显。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号