Enhancement of electrical resistivity of Sr_(0.5)Ba_(0.5)Fe_(12)O_(19) nanomaterials by doping with lanthanum and nickel

摘要

From the viewpoint of electronic and telecommunication devices, the electrical resistivity is required to be high to curb the eddy current losses for efficient performance at high frequencies. In the present work, Sr_(0.5)Ba_(0.5)Fe_(12)O_(19) hexaferrite has been doped with a binary mixture of lanthanum and nickel using chemical co-precipitation method of synthesis. The crystallite size of the synthesized samples is estimated in the range of 36-58 nm and their structural analyses have confirmed a single magnetoplumbite phase. The magnitude of the dc-electrical resistivity is enhanced, by almost 100 times, but Curie temperature (T_C) is reduced by doping with La-Ni, which has been explained on the basis of the exchange interactions. In addition, the doped samples exhibit very low dielectric constant (ε = 11-13) and low dielectric loss tangent (tan δ = 0.07-0.10) determined at a frequency of 1 MHz. These characteristics may be suitable for their potential application in electromagnetic attenuation materials and microwave devices.