Enhancement of dielectric, magnetic and microwave absorption properties of Co2+- Zr4+ substituted SrFe12O19 nanoparticles

Abstract

Co²⁺-Zr⁴⁺ substituted M-type strontium hexagonal ferrite (SrCo_xZr_xFe_12-2xO_19, 0.00 ≤ x ≤ 0.50) nanoparticles were successfully synthesized using sol-gel auto combustion process. The x-ray diffractograms affirmed the development of distinct phase hexagonal ferrite with average crystallite size in the range of 28–35 nm. The fourier transformed infrared spectroscopy identified three distinct modes (between 400 and 650 cm⁻¹), which are consistent with the typical metal-oxygen bonds vibrations at octahedral and tetrahedral sites. All the samples exhibited a homogenous, consistently dispersed spherical shape without agglomeration. The vibrating sample magnetometer analysis revealed an overall increase in the value of saturation magnetization from 40.43 to 50.93 emu/g and remanence from 26.01 to 31.58 emu/g whereas the coercive field decreased from 5790.02 to 4289.89 Oe with increasing Co-Zr concentration. The permittivity and permeability parameters were examined using Agilent network analyzer that disclosed a general increase in both dielectric and magnetic losses with increasing Co-Zr contents $\text{,}$ indicating enhanced energy dissipation behavior. However, the values of magnetic tangent losses are higher than dielectric tangent losses, revealing magnetic loss nature to be the primary loss mechanism for our synthesized nanoparticles. All the compositions showed reflection loss (R_L) below −10 dB in Ku band (12–18 GHz), representing 90 % absorption of incident microwaves. The highest R_L of value −33.42 dB was observed at 14.28 GHz for x = 0.35, revealing the potential candidacy of our synthesized compositions for microwave absorption applications.