UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore 452001, India.
J Phys Condens Matter. 2010 Sep 8;22(35):356001. doi: 10.1088/0953-8984/22/35/356001. Epub 2010 Aug 10.
Bismuth ferrite ceramics (BiFeO(3)) are multifunctional materials classified as multiferroics for their special magnetic and electric properties that can be modified by substitutional doping at the Bi and/or Fe sites. Understanding the relation between magnetoelectric response and structural/electronic modification upon doping is a relevant issue. In this work, the structure of Eu-doped multiferroic systems (Bi(1-x)Eu(x)FeO(3), x = 0, 0.5, 0.1, 0.15) as well as the valence state of Fe and Eu ions have been investigated combining Mossbauer and x-ray absorption fine structure (XAFS) spectroscopy techniques. The Eu(3+) doping at the Bi site results in better magnetic properties. High temperature (57)Fe Mossbauer data and Fe K-edge XAFS results show that FeO(6) octahedron distortions reduce with Eu(3+) doping. It is conclusively shown that the observed magnetic properties in BiFeO(3) with chemical substitution (Eu) are mainly due to the structural distortions and not due to Fe multiple valence. (151)Eu Mossbauer measurements show that the Eu(3+)(Bi(3+)) site is magnetically inactive in BiFeO(3).
铋铁氧体陶瓷（BiFeO(3)）是一种多功能材料，因其特殊的磁电性能而被归类为多铁体，可以通过在 Bi 和/或 Fe 位进行取代掺杂来进行改性。理解掺杂后磁电响应与结构/电子改性之间的关系是一个相关的问题。在这项工作中，结合穆斯堡尔和 X 射线吸收精细结构（XAFS）光谱技术，研究了 Eu 掺杂的多铁体系（Bi(1-x)Eu(x)FeO(3)，x = 0、0.5、0.1、0.15）的结构以及 Fe 和 Eu 离子的价态。Eu(3+)在 Bi 位的掺杂导致更好的磁性。高温（57）Fe 穆斯堡尔数据和 Fe K 边 XAFS 结果表明，FeO(6)八面体扭曲随 Eu(3+)掺杂而减少。可以明确地表明，在化学取代（Eu）的 BiFeO(3)中观察到的磁性性质主要是由于结构扭曲而不是由于 Fe 的多种价态。(151)Eu 穆斯堡尔测量表明，Eu(3+)(Bi(3+))位在 BiFeO(3)中是磁惰性的。
