Development of nanocrystalline Mn–Zn ferrites for high frequency transformer applications

Microwave–Hydrothermal (M–H) method has been successfully used for the synthesis of nanocrystalline Mn–Zn ferrites which are used for high-frequency applications. As synthesized powders were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The nanopowders were annealed at 600 °C/20 min using the microwave sintering method. The frequency dependence of dielectric constant (ε′) was measured in the range of 10 Hz–1.3 GHz and initial permeability (μi) was measured in the range of 10 Hz–1 MHz. The total power loss (Pt) was measured on the annealed samples at 100 kHz and 200 mT condition. Conductor-embedded–ferrite transformers were fabricated and output power (Po), efficiency (η) and temperature rise (ΔT) were measured at sinusoidal voltage of 25 V at 1 MHz. The transformer efficiency (η) was found to be high and surface rise of temperature (ΔT) is very low.