Investigation of grain boundary diffusion and grain growth of lithium zinc ferrites with low activation energy

Activation energy and diffusion kinetics are important factors for grain growth and densification. Here, Bi 2 O 3 was introduced into Li 0.43 Zn 0.27 Ti 0.13 Fe 2.17 O 4 ferrite ceramics via a presintered process to lower the reaction activation energy and to achieve low temperature sintering. Interestingly, Bi 3+ ions entered the lattice and substituted for Fe 3+ in the B‐site (i.e., a pure LiZn spinel ferrite). Also, SEM image results show that Bi 2 O 3 ‐substituted LiZn ferrite ceramics have low critical temperature for grain growth (920°C), which is very advantageous for LTCC technology. This indicates that Bi 2 O 3 is an excellent dopant for ceramics. Furthermore, to promote normal grain growth of the ceramics at low temperatures, different volumes of V 2 O 5 additive were added at the final sintering stage. Results indicate that an optimal volume of V 2 O 5 additive promotes grain growth (with no abnormal grains) and enhances magnetic performances of the ceramics at low sintering temperature. Finally, adding the optimal volume of V 2 O 5 additive resulted in a homogeneous and compact LiZnTiBi ferrite ceramic with larger grains (average size of ~8 μm), high 4π M s (~4100 gauss), and low ΔH (~190 Oe) obtained (at 900°C). Moreover, the doping method reported in this study also provides a reference for other low temperature sintered ceramics.