Improved sintering characteristics and gyromagnetic properties of low-temperature sintered Li.42Zn.27Ti.11Mn.1Fe2.1O4 ferrite ceramics modified with Bi2O3-ZnO-B2O3 glass additive

Abstract New approach for grain size refinement and density increase of low-temperature sintered Ti, Mn codoped LiZn-ferrite (LiZnTiMn) ceramics was developed in this work. It was discovered that excellent gyromagnetic performance could be accomplished for LiZnTiMn ferrite ceramics through controlling the amount of the novel Bi 2 O 3 -ZnO-B 2 O 3 (BZB) flux. Results of X-ray diffraction patterns demonstrated that single spinel structure was obtained at low temperature (~900 °C). Furthermore, scanning electron microscope images of ferrite ceramics indicated that appropriate addition of BZB glass could effectively restrain abnormal grain growth, while simultaneously accelerating densification of low temperature sinterable ferrite ceramics and refining grains (average grain size of approximately 2 µm). Accordingly, when 0.30 wt% of BZB glass was added, ferromagnetic resonance line width (Δ H ) at X-band of ferrite could be significantly decreased from 792 Oe to 161 Oe. In addition, specific saturation magnetization ( M s ) and remanence square ratio ( B r /B s ) also increased to ~ 73.71 emu/g and ~ 0.89, respectively. These enhanced properties demonstrated BZB glass as promising sintering-aid for achieving low-loss LiZnTiMn ferrite ceramics used in microwave LTCC devices.