Synergistic enhancement of mechanical and magnetic properties in MnZn power ferrites via Nano-YIG additives for MHz applications

The rapid development of third-generation semiconductors such as SiC and GaN has driven switching power supply operating frequencies into the MHz regime, imposing increasingly stringent requirements on MnZn power ferrites. In addition to high-frequency, low-loss performance and high saturation flux density, adequate mechanical strength, particularly flexural strength, is essential for reliable device operation. In this work, nano-sized yttrium iron garnet (YIG) is introduced as a multifunctional additive in MnZn power ferrites fabricated via a conventional solid-state reaction route, aiming to simultaneously enhance magnetic and mechanical properties. The results demonstrate that nano-YIG effectively refines the grain structure, reduces porosity, and modulates grain boundary characteristics, leading to increased grain-boundary resistivity. An optimal YIG addition of 0.02 wt% yields a flexural strength of 5.86 MPa, together with enhanced initial permeability, saturation flux density, and cut-off frequency, while significantly reducing the power loss to 943 kW/m3 at 100 °C, 2 MHz, and 50 mT. These findings provide an effective materials design strategy for high-performance MnZn ferrites targeting next-generation MHz-band power applications.