Enhancement in magnetic permeability of Ni‐Co‐Zn ferrites using CuO doping for RF and microwave devices

Abstract Novel soft magnetic ferrite materials will play a crucial role in next‐generation trillion‐dollar sensor technologies related to 5G communications and internet of things as these materials can achieve improved wireless power/signal transfer efficiency with high operation frequency. In this work, Ni 0.4 Co 0.25 Zn 0.35 Fe 2 O 4 ferrites with high permeability and low magnetic loss were prepared for RF and microwave device applications. Composition and microstructure control is crucial to obtain the desired magnetic and loss properties. CuO dopant ( x = 0 wt% to 20 wt%) were employed during the synthesis of Ni 0.4 Co 0.25 Zn 0.35 Fe 2 O 4 ferrite specimens to modify the microstructures, thus improving the magnetic properties of the ferrites. High value of measured relative permeability (μ’ of 4‐10) and relatively low magnetic loss tangent ( of 0.01‐0.1) has been achieved at frequency range between 100 and 800 MHz. Addition of CuO, especially up to 3 wt%, can cause a significant increase in permeability. Real part of the permeability of 3.87 and 10.9 has been achieved for undoped and 3 wt% CuO doped specimens, while noticeable reduction in magnetic losses has been observed for the doped sample measured at 400 MHz. The resonance frequency of synthesized ferrites has also been shifted into GHz range, when higher concentration of CuO dopants (>5 wt%) were employed.