多铁材料BiFeO3的制备与表征

以硝酸铁和硝酸铋为反应物,柠檬酸为络合剂,硝酸为催化剂,采用柠檬酸溶胶–凝胶法制备粒径分布均匀的多铁性材料BiFeO3纳米粉体,通过TG-DSC、XRD、FT-IR、SEM及AFM等手段对样品的结构、形貌及纯净度进行表征.研究结果表明,在溶胶过程中前驱液的pH值以及干凝胶的煅烧温度等合成条件对BiFeO3纳米粉体的制备和纯净程度都有一定的影响,最佳的合成条件是前驱溶液的pH=7～8,干凝胶的煅烧温度为600℃.在该条件下得到的BiFeO3纳米粉体中无杂相Bi25FeO40和Bi2Fe4O9等,纳米颗粒尺寸在100 nm左右,分散性良好,饱和磁化强度Ms=1.08 A·m2/kg,剩余磁化强度Mr=0.13 A·m2/kg,矫顽力Hc=15.76 kA/m.

Preparation and Characterization of Multiferroics BiFeO3

The multiferroic materials BiFeO3 nanopowders of dispersion uniformity were synthesized by the citric acid Sol-Gel method,using the iron(Ⅲ) nitrate and bismuth nitrate as the reactants and dilute nitric acid as the catalyst. The physical and chemical characteristics,such as structure,morphology and purity of BiFeO3 nanopowders were investigated by TG-DSC,XRD,FT-IR,SEM and AFM,respectively.The results indicate that the preparation and purity of BiFeO3 nanopowders have a profound influence on the precursor solution pH value of sol process and the calcined temperature of the xerogel.The optimum reaction conditions are the precursor solution pH=7–8 and calcined temperature of 600℃.It is found that BiFeO3 nanopowders with 100 nm in size,good dispersion and without Bi25FeO40 and Bi2Fe4O9 impurity phase are synthesized under the optimum reaction conditions.The saturation magnetization(Ms),the remanent magnetization(Mr) and the coercivity(Hc) of BiFeO3 nanopowders under the optimum reaction conditions are 1.08 A·m2/kg,0.13 A·m2/kg and 15.76 kA/m,respectively.