Studies of static and high-frequency magnetic properties for M-type ferrite BaFe12−2xCoxZrxO19

Static and high-frequency magnetic properties have been studied for BaFe12−2xCoxZrxO19 with x=0–1.2. The x-ray diffraction and M–H curves of aligned samples show that Co–Zr substitution can modify the anisotropy of BaFe12−2xCoxZrxO19. BaFe12−2xCoxZrxO19 with x⩽0.6 has an easy c-axis anisotropy and the anisotropy fields rapidly decrease with Co–Zr substitutions. The sample of x=1.2 has an easy c-plane anisotropy with Ha=5 kOe. The saturation magnetizations of BaFe12−2xCoxZrxO19 are almost constant at x⩽0.4 and decrease with higher substitutions. The coercivity decreases rapidly from 2400 Oe for the sample of x=0 to about 10 Oe for the sample of x=0.8. The natural resonance frequencies are observed at 4.5 and 5.0 GHz for the samples of x=0.8 and x=1.2, respectively. Based on microwave measurement and theoretical estimations on reflectivity, BaFe12−2xCoxZrxO19 may be a good candidate for electromagnetic compatibility and other practical applications at high frequency.