Influence of admixtures on the properties of biferroic Pb(Fe_(0.5)Nb_(0.5))O_3 ceramic

摘要

The ferroelectromagnetic Pb(Fe_(0.5)Nb_(0.5))O_3 (PFN) ceramic was synthesized by a powder calcining method. The aim of this work was to decrease the electric conduction of the biferroic PFN ceramic as a result of admixing it with metal oxides or carbonates. Investigation results concerning the influence of admixtures of manganese, chromium and lanthanum oxides and potassium and strontium carbonates on direct current electric conduction and dielectric parameters of the PFN ceramic are presented. Crystallographic and morphological studies were carried out using X-ray diffraction and scanning microscopy techniques. The specimens obtained were subjectedrnto dielectric, electric direct current conductivity, hysteresis loop and electromechanical tests. By adding small amounts of admixtures it was possible to decrease (admixtures of manganese or chromium) or increase (admixtures of lanthanum, strontium or potassium) the area of the phase transition of the PFN ceramic. It was found that admixtures of manganese and potassium decreased the electric conduction of the PFN ceramic. PFN admixed with elements of small ions, manganese and chromium, is characterized by a better set of dielectric parameters and lower dielectric losses compared to the PFN ceramic without admixtures.