Magnetic and microwave properties of BaFe12O19 substituted with magnetic, non-magnetic and dielectric ions

Abstract

Barium hexaferrite particles were synthesized with conventional solid state reaction route. 1% boron (B2O3) was added to the initial mixture of oxides to inhibit crystal growth at lower temperatures. Magnetic (Mn2+, Co2+, Ni2+and Cu2+), non-magnetic (Zn2+) and dielectric (Ti4+) ions were replaced by one Fe3+ ion of barium hexaferrite to shift the ferromagnetic resonance frequency to low frequencies and to increase the magnetic and dielectric losses. The structural and morphological characterization of samples was done by X-ray powder diffractometer and scanning electron microscopy. Magnetic and microwave properties were determined by vibrating sample magnetometer and vector network analyzer, respectively. The maximum saturation magnetization and the highest reflection losses of −34dB at 10GHz, with absoption bandwidth of 1.6GHz at −20dB, were observed in Cu2+–Ti4+ and Zn2+–Ti4+ substituted samples. The mechanism of microwave energy dissipation is due to the impedance matching at matching thickness. It was also observed that as the sample thickness increases, the resonance frequency decreases exponentially.