Permeability and electromagnetic wave absorption properties of sintered barium hexaferrites with substitution of Co²⁺–Zr⁴⁺

Abstract

The Co²⁺–Zr⁴⁺ substituted M-type barium hexaferrites with the chemical formula BaCo_xZr_xFe_12−2xO₁₉ (x = 0.0, 0.3, 0.6, 0.9 and 1.2) were synthesized by a sol–gel auto-combustion method. The structural characterizations of the prepared samples were studied using X-ray diffraction and scanning electron microscopy. The complex permeability (μ = μ′ − jμ″) was measured on sintered samples in the frequency range of 100 MHz–3 GHz, and the electromagnetic wave absorbing characteristics of the prepared ferrites with various x value were evaluated from measurements of complex permeability. The results showed that the value of μ and the resonance frequency can be justified by controlling the substituting contents of Co²⁺–Zr⁴⁺. The reflection loss calculations showed that Co²⁺–Zr⁴⁺ substituted barium hexaferrites are good EM-wave absorbers in the quasi-microwave band (1–3 GHz).