Beyond magnetic limits: unveiling the remarkable magnetization of ferrite disk for cutting-edge millimeter-wave applications.

The discovery of high-magnetization soft ferrites is highly beneficial for a wide range of applications supporting satellites and radar systems by enabling nonreciprocal microwave devices to efficiently operate at millimeter-wave and sub-terahertz frequency spectrums. However, the maximum available ferrites in the microwave and space industries have a magnetization saturation of approximately 5300(G), which limits the development of nonreciprocal microwave devices above 40 GHz. Here, we investigate a soft ferrite disk with a high magnetization 4πMs exceeding 11250(G), which is more than double that of the currently commercially available materials in the microwave and space industries. The high saturation magnetization of a Nickel-Zinc ferrite Ni0.5Zn0.5Fe2O4 powder is achieved by heating at 1100 °C for 4 h in a Nitrogen + 3% H2 gas environment. The magnetic and structural properties are demonstrated by X-ray diffraction (XRD) and vibration sample magnetometer (VSM), which show a high magnetization saturation of 174 emu/g. Later, electromagnetic investigations using the Vector Network Analyzer (VNA) exhibit a loss tangent of 0.00115 and a dielectric constant of 14.5. This newly proposed fabrication technique for producing Nickel-Zinc ferrites will mark a significant breakthrough in the microwave and space industry supporting various future applications in the millimeter-wave spectrum.