Synergistic Modulation of Magnetic and Dielectric Properties via La‐V Co‐Substitution in Barium Hexaferrite for Advanced Millimeter‐Wave Absorption

The growing deployment of high‐frequency electronic systems has intensified the demand for high‐performance microwave absorption materials. In this work, we developed La‐V co‐substituted barium hexaferrites, Ba 1‐ x La x Fe 11.9 V 0.1 O 19 (BLFVO), via a sol‐gel route. Comprehensive structural and electromagnetic analysis reveals that the co‐substitution induces synergistic magnetic and dielectric loss, leading to significantly improved impedance matching and attenuation capacity. The optimized sample achieves both a significantly reduced matching thickness and a broadened effective absorption bandwidth (EAB) in the Ka‐band (26.5–40 GHz). Specifically, within the Ka‐band, the BLFVO ( x = 0.4) sample achieves an effective absorption bandwidth of 7.29 GHz, a minimum reflection loss of −15.17 dB, and a matching thickness of 0.7 mm. Furthermore, the material also exhibits respectable absorption performance in the 2–18 GHz range, and its overall practical potential is confirmed by radar cross‐section (RCS) simulations. This study offers valuable insights for the rational design of ion‐substituted ferrites as high‐performance microwave absorbers.