부산대학교 도서관

The effect of Pb substitution on the structure, dielectric, impedance and magnetic properties of Li0.5+0.5xFe2.5-1.5xPbxO4 ferrite nano-crystals prepared by citrate gel method has been investigated. X-ray diffraction analysis confirmed the formation of cubic spinel phase and broadness of reflection peaks indicates the formation of smaller sized crystallites. The average crystallite size was observed to increase from 21.3 to 26.1 nm on increasing Pb substitution in Li0.5+0.5xFe2.5-1.5xPbxO4 ferrite. The surface analysis of the samples was performed using scanning electron microscopy. An improvement in the microstructure has been obtained on Pb doping. Dielectric and impedance measurements were carried out in the frequency range of 100 Hz-10 MHz. The dielectric properties of Li0.5+0.5xFe2.5-1.5xPbxO4 ferrite samples were improved much by the substitution of Pb ions. The low dielectric loss at higher frequencies identifies the potential of these ferrites for high frequency applications. Interestingly, a very large value for dielectric constant of the order of 107 has been obtained on Pb doping. The impedance spectroscopy technique was used to study the effect of grain and grain boundary on the electrical properties of the material. From the present investigation on Li0.5+0.5xFe2.5-1.5xPbxO4 ferrite, one can conclude that the substitution of Pb4+ ions play an important role to modify the magnetic and electrical properties of lithium ferrite desired for microwave devices and power applications. [ABSTRACT FROM AUTHOR]