Tunable M-type nano barium hexaferrite material by Zn²⁺/Zr⁴⁺ co-doping

Abstract

The effect of Zn2+/Zr4+ dopant ions on the physical and magnetic properties of BaZnxZrxFe12−2xO19 (x = 0.00 to 0.80) synthesized using sol-gel auto combustion method has been investigated. FE-SEM micrographs reveal a decrease in average particle size from ≈350 nm to ≈115 nm with increase in Zn2+/Zr4+ dopant concentration. XRD reveals the formation of M-type hexaferrite (NBaM) pure phase and the absence of secondary impurities such as α/γ –Fe2O3 and BaCO3. The lattice parameters increase and the crystallite size has been found to decrease with increasing Zn2+/Zr4+ dopant concentration. The widening of Raman bands reveals local distortion of the crystal structure with increasing dopant ion concentration. Magnetic measurements reveal that the sample exhibit magnetic ordering and a gradual change in magnetic nature from hard to soft ferrite with increasing substitution of Zn2+/Zr4+ ions. The coercivity value decreases from 4686 Oe to 776 Oe with increasing Zn2+/Zr4+ dopant concentration. The saturation magnetization (Ms) value has been found to be maximum (61.53 emu g−1) in x = 0.40 sample. The shift in Tc from 711.9 K to 522.8 K with composition confirmed the weakening of super exchange interaction in these samples. These materials could be useful for magnetic recording applications.