磁性离子Fe掺杂钛酸钡铁电材料的结构和物性研究

Structural and Physical Properties of Magnetic Ion Fe-doped BaTiO_3 Ferroelectric Materials

采用高温固相反应法制备了铁掺杂的钛酸钡BaTi1-xFexO3(0.10≤x≤0.60)样品,研究了其结构、铁电和磁学性质。X射线衍射谱表征了铁掺杂钛酸钡材料的结构,确定了BaTi1-xFexO3样品为四方相结构,晶体结构精修表明掺杂离子的引入使得BaTi1-xFexO3材料的晶体结构在ab面发生了扩张,而沿c轴方向收缩。X射线光电子能谱研究了材料的化学成分和表面化学价态,表明三价和四价铁离子同时存在于晶格中,并取代四价钛离子而形成了BaTi1-xFexO3结构。样品的介电温谱和磁滞回线表明BaTi1-xFexO3材料在室温下同时具有铁电性和铁磁性。随着Fe掺杂量由10%增加至60%,单个铁离子在材料中产生的磁矩由0.70μB增加到1.55μB。通过对样品磁性的分析发现,材料的铁磁性来源于铁离子和氧离子的双交换作用。

The structural,ferroelectric and magnetic properties of bulk perovskite Fe-doped BaTiO3 prepared by standard solid-state reaction have been investigated. X-ray diffraction identifies the tetragonal structure of Fe-doped BaTiO3（BFTO） samples,and Rietveld refinements of XRD data indicates that the doping ions led to ab plane expansion and out-of-ab-plane shrinkage of the Fe-doped BaTiO3 phases. Xray photoelectron spectroscopy（XPS） measurements for the prepared samples reveals that Fe3 ＋and Fe4 ＋replaces Ti4 ＋in the crystal lattice to form single phase BFTO solids. The results of the temperature dependent dielectric properties and magnetic hysteresis loops for the Fe-doped BaTiO3 solids show simultaneously the ferroelectric order and ferromagnetic order at room temperature. The doping of magnetic element Fe brings about ferromagnetic order for the samples and the measured magnetic moment for each Fe atom increases from 0. 70 μBto 1. 55 μBin BFTO samples. The origin of ferromagnetism of the BFTO samples should be attributed to the double exchange interactions of Fe3 ＋-O2--Fe4 ＋.