Microwave absorption properties of SrxBa3-xCo2Fe24O41 hexaferrites in the range of 0.1-18 GHz

Sr(x)Ba(3-x)Co(2)Fe(24)O(41)Z-type hexaferrites have been prepared by the citric acid sol-gel method, and the structural and electromagnetic properties have been investigated in detail. The results showed that single-phase Z-type hexaferrites were observed, and all samples exhibited excellent soft magnetic properties. For the sample with x = 1.5, a high resonant frequency f(r) = 3.50 GHz and initial permeability mu' = 2.76 at 100 MHz was obtained. The calculated frequency dependence spectrum of the reflection loss (RL) showed a largest absorbing value of -48.5 dB at 17.6 GHz with a thickness of 5.0 mm. With the increasing thickness t, two local minimum RL values were observed from the RL-t curve. One was -43.6 dB at t = 4.3 mm and the other was -45.8 dB at t = 2.8 mm. The dependence of percentage bandwidth W-p on thickness t was studied. As t increasing, W-p increased firstly and then slowly decreased, reaching the maximum value of 96.1% at t = 3.3 mm. (C) 2018 Elsevier B.V. All rights reserved.