Research on magnetic and microwave absorbing properties of Co₂Y ferrite fabricated by sol–gel process

Abstract

The Co₂Y ferrite was prepared by sol–gel method, and its morphology, phase structure, magnetic, and electromagnetic parameters were investigated by related equipment. The results testified that the saturation magnetization which was measured by vibrating sample magnetometer (VSM) gradually decreases as the sintering temperature increases. The microwave absorbing peaks of Y-type ferrite moves to higher frequency with the rise of temperature. The minimum reflectivity value of the Y-type ferrite powder can achieve about −24.82 dB at 11.68 GHz with a thickness of 8.0 mm and the effective bandwidth (R < −10 dB) is 2.56 GHz. In addition, the microwave absorbing peaks of Nickel/Co₂Y ferrite mixture moves to a lower frequency with the addition of nickel power. The minimum reflection loss value of mixture that consist of 40% nickel and 60% Y ferrite was −33.75 dB at 4.88 GHz (in the C-band) with the thickness of only 2.5 mm. These indicate that the combination of alloy powder and ferrite can improve the reflection loss value of ferrite at low thickness.

Highlights

• The saturation magnetization (M_s) of Co₂Y ferrite, which was prepared by a sol-gel method, decreases from 54.46 to 48.04 emu/g with the increasing sintering temperature.

• The Co₂Y ferrite prepared by a sol-gel method can reach the minimum reflection loss of −24.82 dB at 11.68 GHz with the thickness of 8.0 mm, and a bandwidth of R < −10 dB is 2.56 GHz.

• The optimum microwave absorption performance can be achieved for 40% nickel content, and a minimum reflection loss of −33.75 dB was obtained at 4.88 GHz with the thickness of 2.5 mm.