Abstract
B-Cr-substituted Y-type hexa-ferrites were prepared via a micro-emulsion method. Formation of the hexagonal phase was confirmed by X-ray diffraction (XRD) analysis. The size of the crystallites of all the samples was in the range 31.58-37.67 nm and their Fourier transform infrared (FTIR) spectroscopy bands were observed in the range similar to 450-650 cm(-1). These bands indicated successful incorporation of Bi-Cr in the Y-type hexagonal ferrites. The existence of metal-oxygen bands at the tetrahedral and octahedral sites confirmed that all the prepared samples exhibit Y-type hexagonal ferrites structures. The magnetic parameters such as saturation magnetization, retentivity and coercivity revealed significant variations with the increase of Bi-Cr contents. Frequency and composition dependent variations in the dielectric constant (epsilon '), dielectric loss (epsilon ''), tan loss, and other parameters were observed, for example the value of epsilon ' decreased as the Bi-Cr content increased. These optimised results are highly desirable for the application of these nanosized hard ferrites in various microwave devices