Li 2 O–B 2 O 3 –SiO 2 –CaO–Al 2 O 3 glass-doped NiCuZn ferrite with high permeability and reliability for high-frequency MLCI application

Miniaturization, high-frequency capability, and high reliability are important indicators for the practical applications of multilayer chip inductors (MLCIs). Although ferrites offer significant advantages as an MLCI material, some challenges are still required to be resolved before using them in higher-performance applications. Low-temperature fired ferrites have been doped to optimize their magnetic properties and adjust their microstructure. In this study, the growth of (Ni 0.2 Cu 0.2 Zn 0.6 O) 1.03 (Fe 2 O 3 ) 0.97 (NiCuZn) ferrites doped with different amounts of Li 2 O–B 2 O 3 –SiO 2 –CaO–Al 2 O 3 (LBSCA) glass was investigated by sintering at 920 °C. All samples exhibited single-crystalline phase structure as revealed by X-ray diffraction analysis. Magnetic properties of ferrites were also greatly improved. In particular, real part of magnetic permeability of NiCuZn samples increased from 282.14 to 442.98 at 1 MHz for the LBSCA glass content of 0.18 wt%, and its cut-off frequency increased by a significant factor of two. Samples with 0.18 wt% LBSCA exhibited high saturation flux density (5.29 g cm −3 ) and low coercivity (43.62 A m −1 ), as well as saturation magnetization of 3784.23 G. It was found that LBSCA-doped NiCuZn ferrites exhibited chemical compatibility with Ag, thus meeting the application criteria for low-temperature co-fired ceramics. Results show that the incorporation of LBSCA glass endows NiCuZn ferrites with outstanding magnetic characteristics and compact, homogeneous microstructure.