Significantly enhancing electromagnetic wave absorption properties of BaFe12O19 hexaferrites via KOH mineralizer

Abstract

To further study the microwave absorbing properties of hexagonal barium ferrites (abbreviated as BaM) fabricated by using an innovative hydrothermal method with different mineralizers, the crystal structure, morphology, magnetoelectric and the microwave absorption properties of BaM were systematically studied. X-ray diffraction patterns (XRD) show that all samples exhibit a pure phase for BaM. At the same time, the grain size and morphology can be controlled and the thicker and regular hexagonal flakes were obtained using KOH mineralizer. The maximal magnetization in the field 15 kOe of BaM can be improved by using KOH mineralizer compared to NaOH mineralizer, while the coercivity (Hc) is slightly reduced. The maximal magnetization in the field 15 kOe is 31.83 emu/g and 43.36 emu/g for BaM synthesized with NaOH and KOH mineralizers, and the Hc is 860.23 Oe and 842.00 Oe, respectively. Meanwhile, the RL values of BaM synthesized with NaOH mineralizer are greater than − 3.00 dB indicating poor absorbing property. While, as for the BaM synthesized with KOH mineralizer, the electromagnetic wave absorption performance is enhanced greatly. The minimum value of the reflection loss (RLmin) is − 17.59 dB obtained at 13.2 GHz with a thickness of 1.5 mm, and the effective absorption bandwidth is up to 3.2 GHz (11.6∼14.8 GHz) for BaM with KOH mineralizer. This work provides a kind of effective method to enhance the microwave absorption properties of BaM material by changing the mineralizer, and suggests that BaM is a microwave absorbing material with great potential engineering applications for 5 G communication.