High-temperature 0.5BiFeO3-0.5PbFe0.5Nb0.5O3 multiferroic: Microstructure, ferroelectric properties, and Mossbauer effect

Research findings of the microstructure, dielectric, ferroelectric characteristics, and Mossbauer effect of solid solution ceramics with 0.5BiFeO(3)-0.5PbFe(0.5)Nb(0.5)O(3) composition in a wide temperature range are presented. The examined ceramic chip surface allows one to draw conclusions about the internal homogeneity of grains and the absence of pores inside them. It was shown that Fe3+ iron cations in the material are valence and they are found only in seven locally different states, which is associated with disorder in the solid solution structure. The Neel temperature is T-N similar to 445 K. The anomalous behavior at T < 30 K becomes clear when analyzing the dielectric spectra of 0.5BiFeO(3)-0.5PbFe(0.5)Nb(0.5)O(3) ceramics in the range of 10 ...1000 K. It is explained by the appearance of a spin-glass state in the object. The presence of contributions to the dielectric response in ceramics at T > 300 K is revealed. It is claimed that the ferroelectricrelaxor -> paraelectric phase transition caused the low-temperature contribution, and the second one is a manifestation of the Maxwell-Wagner polarization and the corresponding non-Debye type dielectric relaxation. The causes of the revealed regularities and the prospects for using the material in the thin films form are discussed.