Thickness independent microwave absorption performance of La-doped BaFe12O19 and polyaniline composites

•Ba1-xLaxFe12O19/polyaniline composites were successfully prepared.•RL maintained at a specific value for all measured thicknesses for each composites.•≥ 90% of incident wave being absorbed for Ba0.9La0.1Fe12O19/PANI (t = 1.75–3.50 mm).•Effective bandwidths of Ba0.9La0.1Fe12O19/PANI increased by thickness decreasing. Absorber thickness is a crucial factor in microwave absorption performance. Therefore, the researches about the influence of thickness on microwave absorption performance have been intensively investigated. In this work, we prepared La-doped BaFe12O19 with a concentration of 0, 0.1, 0.3, and 0.5 by using co-precipitation then mixed with polyaniline by 10% wt. Morphological, structural, magnetic, and electromagnetic properties were evaluated using SEM, XRD, VSM, and VNA analysis. The doping modified all the properties of the samples and consequently enhanced their microwave absorption properties. The La-doping and polyaniline compositing possessed significance for maintaining reflection loss values for all composites when the absorber thicknesses varied in the range of 1.75–3.50 mm. The best microwave absorption performance could be found in the Ba0.9La0.1Fe12O19/polyaniline (named La-P1) composite, with more than 90% of the incident wave being absorbed for all measured thicknesses. Effective bandwidths of the La-P1 increased when thickness decreased and reached a maximum of 2.52 GHz for the thickness of 1.75 and 2.00 mm.