The tunable microwave absorption properties of the Co²⁺–Zr⁴⁺ co-substituted Co₂W-type hexagonal ferrites

Co²⁺–Zr⁴⁺ co-substituted W-type hexagonal ferrites with chemical composition BaCo₂Fe_16−x(Co_0.5Zr_0.5)_xO₂₇.(x = 0.0, 0.4, 0.8, and 1.2) have been synthesized using a sol–gel self-propagating combustion method. The phase and microstructure were determined using XRD and FESEM, respectively. The results show that the diffraction peaks of all samples are in accordance with W-type ferrite phase without other impure phases. The flake-shaped crystals are formed when x ≤ 0.4, and changed into irregular particles with further increasing x. The electromagnetic parameters have been measured in the frequency range of 1 to 18 GHz using a vector network analyzer. The ε′ and ε′′ of ferrite are increased in whole frequency and the magnetic resonance peak shift to high frequency when x = 0.4. It can be observed that composition x = 0.4 possesses highest RL peak of − 28.63, − 37.84, and − 21.98 dB at 15.70, 16.30, and 16.98 GHz when the thickness is 5.2, 5.0, and 4.8 mm, respectively. And it also exhibits − 10 dB wideband absorption bandwidth of 1.87 GHz, 2.47 GHz, 2.72 GHz, and 2.21 GHz when the thickness ranges from 4.8 to 5.5 mm. The microwave absorption can be tuned by thickness and substitution of Co²⁺ and Zr⁴⁺ ions. The large RL suggests that the compositions could play a great potential in the application of microwave absorbing technology.