Microstructure and gyromagnetic properties of low-sintered M-type barium hexagonal ferrite with various Ga3+ ions substitutions

Abstract

The adjustment of crystal structures and properties by ion substitution has received increasing interest in recent years to solve issues related to the preparation of LTCC microwave devices. In this work, Fe3+ ions were substituted in BaFe12O19 sintered at a low temperature (920 °C). The changes in microstructures, dielectric characteristics, and magnetic properties were all examined. The ferromagnetic resonance linewidth (ΔH) of BaM ferrite was measured at magnetic fields from 6000 to 24,000 Oe. The results revealed well-grown microstructures of BaM ferrite grains at 920 °C to form typical hexagonal structures. The increase in substitution of Ga3+ ions decreased the lattice constant and cell volume of the crystals. More interestingly, the dielectric and magnetic properties depicted significant changes in the original dielectric and magnetic parameters of BaM after the substitution of Ga3+ ions. The permittivity (ε′) rose to a maximum of 16.36 at x = 0.4, while the dielectric loss angle tangent (tan δε) declined to 1.2 × 10^−3. As Ga3+ ions rose, the saturation magnetization 4πMs decreased from 3168.58 Gauss to 2571.18 Gauss. The remanence (Mr) reached a maximum value of 31.07 emu/g at x = 0.4. The ferromagnetic resonance linewidth (ΔH) of BaM ferrite sample at 31 GHz attained a minimum value of 4216.336 Oe at x = 0.8. In sum, these findings look promising for future fabrication of LTCC microwave RF devices.