The effects of microstructure on the magnetic properties of MgCuZn ferrites applied in near field communication

• We demonstrate the MgCuZn ferrite can be applied to NFC system.
• The Q factor at 13.56 MHz is 33.40.
• The sample with small grains possesses the satisfactory magnetic properties.
• The sample with the lowest β possesses the best magnetic properties.

The magnetic properties of MgCuZn ferrite samples with varied microstructures prepared by conventional solid-state reaction method were studied for the application of the near field communication (NFC) system. The results show that the densely sintered sample with small grains possesses the most satisfactory magnetic properties. Specifically, the Q factor, the real and imaginary part of the permeability of the sample at the frequency of 13.56 MHz are 33.40, 117.22 and 3.51 respectively. Furthermore, the effects of microstructure on the permeability spectra of the ferrite samples are investigated systematically via the numerical fitting method. It is observed that both grain size and pore greatly impact on the static susceptibility of domain wall motion Kdw, and static spin susceptibility Kspin, and the damping factor of the domain wall motion β is greatly affected by the closed pores. The theoretical analysis indicates that lowering β is more significant than adjusting Kdw or Kspin for the purpose of high real part of permeability and Q factor. Based on theoretical expectation, the better magnetic properties can be obtained by the further improvement on the microstructure of materials.