Comparative evaluation of different sol–gel processed M-type barium hexaferrite on structural and antimicrobial efficacy

Barium hexaferrite has gained increasing attention for biomedical applications, including antimicrobial coatings and targeted drug delivery alongside its established use in magnetic solid-state devices. Therefore, understanding how synthesis routes influence its formation and biological performance is essential. In this study, M-type barium hexaferrite BaFe 12 O 19 (BHF) was synthesized via two distinct sol–gel processes: sol–gel auto-combustion and a dried-gel (non-combustion) method, followed by systematic sintering to optimize phase formation. Structural, morphological, and chemical properties were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and N 2 physisorption BET measurements. XPS analysis revealed that the non-combustion route yields a cleaner, low-defect crystal structure, whereas auto-combustion promotes complete Fe 3 + phase formation accompanied by higher surface defects and oxygen vacancies. Nitrogen adsorption isotherms confirmed mesoporous Type IV behavior for both methods, with the combusted sample exhibiting a higher specific surface area ( 7.81 m 2 / g ), greater N 2 uptake, and a narrower pore size distribution. Antimicrobial evaluation against Gram-positive and Gram-negative bacterial strains using the agar well diffusion method showed that while synthesis routes markedly influence crystal purity, defects, and morphology, they induce only minor variations in antimicrobial activity with auto-combusted samples exhibiting a slight reduction in efficacy. These findings demonstrate that functional properties of BaFe 12 O 19 can be tailored through controlled synthesis, highlighting its potential as a multifunctional platform for integrated magnetic and biomedical applications.