Design of multifunctional rare earth Dy–Ce substituted BaFe12O19 nanoparticles for X-band microwave absorption and EMI shielding

Cole–Cole analysis reveals non-Debye-type relaxation , validating enhanced dielectric response in doped samples. • Dy 3 + and Ce 3 + co-substitution at Fe 3+ sites in BaFe 12 O 19 improves electromagnetic wave absorption and magnetic softness. • High saturation magnetization of 63.07 emu/g achieved at x = 0.06 composition, confirming enhanced spin alignment. • Strong microwave absorption with maximum reflection loss of − 17.64 dB at 9.54 GHz, indicating > 90 % absorption. • EMI shielding mechanism shifts from reflection to absorption with rare-earth doping, favoring stealth applications. • FTIR, ESR, and XRD confirm successful RE doping and retention of hexagonal magnetoplumbite structure. The growing demand for compact and efficient solutions in electromagnetic interference (EMI) shielding and microwave absorption has intensified research into advanced magneto-dielectric nanomaterials materials that exhibit both magnetic and dielectric loss mechanisms. Among these, M−type barium hexaferrites (BaFe 12 O 19 ) have gained attention due to their high magnetocrystalline anisotropy, thermal stability, and natural resonance properties. However, their limited absorption bandwidth and moderate efficiency in the X-band frequency range (8–12.4 GHz) restrict practical applications in modern communication systems and defense technologies. In this work, we report the synthesis of rare-earth co-substituted barium hexaferrite nanoparticles, specifically BaDy x Ce x Fe 12-2x O 19 (where x = 0.00–0.10), via the sol–gel auto-combustion method, a soft-chemical route known for producing fine, homogeneously doped nanopowders. The structural, morphological, and electromagnetic properties were systematically investigated using X-ray diffraction, scanning electron microscopy, electron spin resonance, vibrating sample magnetometry, and vector network analysis. The composition with x = 0.06 exhibited the most favorable performance, achieving a maximum reflection loss (RL) of − 17.64 dB at 9.54 GHz, along with a shift from reflection-dominated to absorption-dominated EMI shielding behavior. These improvements are attributed to enhanced magnetic softness, optimized dielectric and magnetic losses, and improved impedance matching between the material and free space. This study presents a promising dual rare-earth doping strategy for tailoring the microwave response of ferrites. While the present work focuses on fixed absorber thickness and ambient conditions, future research will explore flexible composite fabrication, broadband absorption behavior, and environmental stability for practical deployment in stealth and EMI shielding technologies.