Liquid phase sintering of ferrite of NiCuZn with low magnetic permeability for miniaturization

In this study, we synthesized ferrites with the formula Ni0.5−xCuxZn0.5Fe2O4 and sintered them to x = 0, 0.1, 0.2 and 0.3 using the citrate precursor method. We then analyzed the sintered toroids by X-ray diffraction (XRD) with Rietveld refinement. Scanning electron microscopy (SEM) results showed there to be uniform grains in NiZn, abnormal grains at x = 0.2 with a remnant of the CuO liquid phase, and large grains at x = 0.3. We then analyzed the toroids by vibrating sample magnetometry (VSM). The hysteresis reached a saturation magnetization (Ms) value of 88.37 emu/g and a coercive field (Hc) of 0.0016 T. We calculated the Bohr magnetons using the Ms information and obtained the magnetic permeability with a vector network analyzer (VNA). The toroid with the remnant CuO phase showed relative permeability values of between 20 and 30 and low losses in a wide range of frequencies (10-50 MHz), which we attribute to the microstructure characteristics. Based on our results, this ferrite can be used in the miniaturization of magnetic components used in electro-electronic devices.