The influences of hot-pressing temperature and second sintering on microstructure and gyromagnetic properties of LiZnTi ferrite

In this study, a hot-pressing sintering (HPS) was firstly performed for LiZnTi ferrites sintered from 850 to 1050 °C. To analyze feasibility of co-firing, the as-sintered HPS 1st samples were then subjected to a traditional sintering (TS) process at 950 °C. The influences of sintering temperature and second sintering on the crystal phase formation, microstructure, and gyromagnetic properties of the LiZnTi ferrite were systematically investigated. X-ray diffraction confirmed that all the samples exhibited a pure spinel structure. SEM images indicated that the grain size and bulk density of the samples have increased with the increase in temperature. Due to the second sintering with a long time, all the samples exhibited a secondary growth. The magnetic hysteresis (M-H) loops confirmed that sintering temperature could enhance saturation magnetization intensity and the samples kept a stable value after second sintering. The results of ferromagnetic resonance (FMR) linewidths revealed that the 1000HPS 1st sample had a small value ( ΔH  = 298.25 Oe) and could also keep a good and stable value after second sintering. Thus, the LiZnTi ferrite sample prepared by hot-pressing sintering was feasible for co-firing with other ceramic (dielectric ceramic) for microwave applications.