Design and fabrication of low-loss high-permeability soft magnetic mouldable composites for high-frequency power inductor applications

Soft magnetic mouldable composites ((SMCs)-Cs-2) would be ideal for integrating magnetic core inductors into circuits since they can be fabricated at low temperatures and pressures. However, most of the existing (SMCs)-Cs-2 offer either low magnetic permeability (mu ') or low quality factor (Q), especially at high frequencies (> 10 MHz). To address this issue, a bottom-up approach is reported that incorporates designing the composition of the magnetic filler, coating the filler with Polydimethylsiloxane (PDMS) brush, to a state-of-the-art casting process. This procedure has enabled the fabrication of cores with an outstanding combination of mu ' and Q. The mu ' of our cores is 40% higher than the best available data at 10 and 25 MHz which is due to the high packing of cores. Our core also offers one of the highest Q at 10 MHz due to low hysteresis loss and low inter-particle eddy current loss as a result of the polymer brush insulating effect.