Preparation and investigation of structure, magnetic, and dielectric properties of (1 − x )Bi 2 Fe 4 O 9 – x MgFe 2 O 4 bicomponent ceramics

Crystal structure, morphology, magnetic, and dielectric properties of (1 − x )Bi 2 Fe 4 O 9 – x MgFe 2 O 4 bicomponent ceramics are investigated in detail. The material has been synthesized via sol–gel method. Analysis of X-ray diffraction data of the bicomponent ceramics shows the coexistence of orthorhombic Bi 2 Fe 4 O 9 and spinel MgFe 2 O 4 phases with no third phase. Microstructural and surface morphology displays the homogeneous grain distribution with different grain sizes of Bi 2 Fe 4 O 9 and MgFe 2 O 4 . The magnetic measurement shows decreasing coercivity and increasing values of remnant and saturation magnetization with the increase in MgFe 2 O 4 . Temperature-dependent dielectric properties and electrical modulus are conducted in the temperature range of 27–527 °C with the frequency ranging from 1 to 30 kHz. Two abnormal peaks are, respectively, observed at low and high temperature ranges. The variation of electric properties is closely related to the composition of MgFe 2 O 4 . The results of dielectric and electrical modulus indicate the appearance of dielectric relaxation in (1 − x )Bi 2 Fe 4 O 9 – x MgFe 2 O 4 . Combined with the study of activation energy, the dielectric relaxation is mainly induced by different electric responses of various charge carriers intrinsically dominating in a thermally activated process with the incorporation of MgFe 2 O 4 . The combination of Bi 2 Fe 4 O 9 and MgFe 2 O 4 enhances the coexistence of magnetic and electric properties in the present composites. It is quite promising from application point of view.