In situ synthesis of Zr4+ doped BaFe12O19/Fe3O4 composites for enhanced centimeter and millimeter wave absorption compatibility

Abstract

To effectively tackle the intricate electromagnetic pollution arising from the rapid advancements in network technology, it is crucial to develop a wide-frequency, highly efficient absorbing material that can simultaneously demonstrate absorption properties for both centimetre-wave and millimetre-wave frequencies. In this study, a hydrothermal method followed by heat treatment is utilized to fabricate the hard-soft magnetic BaZr_xFe₁₂O₁₉/Fe₃O₄ composites. The doping quantity of Zr⁴⁺ ions is modulated in order to regulate the electromagnetic parameters and magnetocrystalline anisotropy of the composites to response concurrently in both centimetre-wave and millimetre-wave bands. This is achieved by utilising the interface exchange coupling between the hard magnetic barium ferrite and the soft magnetic triiron tetraoxide, generating multiple resonant magnetic permeability and enhanced magnetic permeability characteristics. When the heat treatment temperature is set at 700°C, with a doping concentration of Zr⁴⁺ at x = 0.1 and a matching thickness of 2 mm, it has been observed that the total effective absorption bandwidth reaches its maximum value of 10.74 GHz. The coverage within the frequency bands of 2-18 GHz and 26.5-40 GHz is measured to be 3.68 GHz and 7.06 GHz, respectively. This finding presents an entirely new concept for the development of advanced microwave absorbing materials characterized by a broader range of applications.