Microwave-absorbing properties of strontium ferrites prepared via sol-gel method

Strontium ferrites were prepared by sol-gel method, the phase structure, morphology, and microwave absorbing properties of the samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vector network analyzer (VNA). The results show that with increasing sintering temperature, the wave-absorption peak frequency moves towards low-frequency direction and the reflection loss value decreases first, and then increases. At the same sintering temperature (1200 degrees C) and different holding time (2h, 4h, 6h, 8h), the ferrites have the same Z-type phase structure. With increasing holding time, the absorption peak frequency of the ferrites shift towards low-frequency region, and the minimum reflectivity value decreases first and increases afterwards, and the ferrite holding at 1200 degrees C for 4 h has the best microwave-absorbing property.