High permeability and low loss flaky carbonyl iron soft magnetic composite for 5G applications

A soft magnetic composite (SMC) material with a large aspect ratio is prepared by a ball-milling method. Such SMCs have excellent high-frequency performance such as high permeability, saturation magnetization, and resonance frequency, which makes them have great potential in the field of 5G and high-frequency power devices. The flaky particles with large aspect ratios can effectively reduce eddy current loss and obtain larger permeability. Simultaneously, we also further studied the high-frequency magnetic properties and loss of SMCs with different aspect ratios. We obtained the magnetic spectra of samples with different aspect ratios and then established a loss model for flaky samples under high frequency and performed loss separation for these samples. The relationship between the aspect ratios, permeabilities, and three types of loss after separation is analyzed and discussed. A large aspect ratio can effectively improve the permeability and reduce the eddy current loss, and a high permeability due to a large aspect ratio can also reduce the hysteresis loss. The differentiation of magnetic domain and the variation in the number of domain walls caused by the process of obtaining the large aspect ratio (ball milled), high permeability caused by this process and number of displaced domain walls also affect the excess loss. This provides the possibility for the application of soft magnetic material composites at high frequencies.