Low-temperature sintering and ferromagnetic properties of Li0.35Zn0.30Mn0.05Ti0.15Fe2.15O4 ferrites co-fired with Bi2O3-MgO mixture

In the present work, Li_0.35Zn_0.30Mn_0.05Ti_0.15Fe_2.15O₄ ferrites were successfully synthesized via solid-state reaction method with the assistance of Bi₂O₃-MgO mixture. It was observed that a pure spinel phase could be formed at low temperatures (880 °C–920 °C), suggesting the compatibility of co-firing with silver internal electrodes. The employment of Bi₂O₃-MgO mixture could not only achieve the low-temperature sintering, but also facilitate the grain growth and subsequently promote the magnetic properties. SEM results revealed that the ferrites grain size was significantly increased (from 1 to 20 μm) with an appropriate dopant addition (1.2 wt %). Meanwhile, the saturation induction was enhanced from 141.2 to 345.9 mT, the coercivity was decreased from 515.2 to 176.6 A/m, and the FMR linewidth was dramatically decreased from 749.0 to 245.0 Oe at 9.3 GHz. Thus it is expected that the improved properties will allow the Li_0.35Zn_0.30Mn_0.05Ti_0.15Fe_2.15O₄ ferrites to be a promising candidate for low temperature co-fired ceramics (LTCC) applications.