High permeability and low loss bioinspired soft magnetic composites with nacre-like structure for high frequency applications

Abstract

Bioinspired Soft Magnetic Composites (SMCs) with nacre-like structure were fabricated using highly planar arranged flaky-Sendust. These SMCs show particularly high permeability and low loss, thus exhibiting great potential for high frequency magnetic components. Due to the high saturation magnetization and permeability of metal soft magnetic materials, it is possible to miniaturize magnetic devices by reducing the total loss, especially the eddy current loss at high frequency. The new SMCs with nacre-like structure exhibited a high permeability of up to 600 at 1 MHz, which was ten times that of common Sendust composites. The total loss decreased to 470.82 and 1162.60 kW/m3 at 100 and 200 kHz, respectively (stimulated at 100 mT), and the maximum magnetic induction increased to 714 mT at 8000 A/m, which was superior to that of ferrites. This outstanding comprehensive property is a result of the anisotropic demagnetizing factor of the flaky particles in a planar arrangement, which can be derived from the Aharoni's formula. The minimum total loss is a result of the balance of hysteresis and eddy current loss for the small thickness, which is below skin depth. In addition, the three-dimensional loss separation characteristic was analyzed using the nonlinear regression method to theoretically evaluate the influencing factors related to the morphology of the materials. This approach provides small, high frequency, and high saturation magnetic devices for switching regulators, photovoltaic inverter boost inductors, and noise filters.