Exploring the electromagnetic shielding behavior of lanthanum doped calcium nanoferrites

Abstract

The present study focuses on the synthesis and characterization of lanthanum (La³⁺)-doped calcium nanoferrites (CaLa_xFe_2–xO₄; x = 0.025, 0.050, 0.075 and 0.100) using the sonochemical method. Various techniques were employed to analyze the effect of La³⁺ infusion. Raman spectroscopy confirms the presence of active A_1g, T_2g and E_g modes in the CaLa_xFe_2–xO₄ nanoferrite, indicating the formation of an active ferrite system. The introduction of La³⁺ doping results in a significant increase in the band gap energy, rendering the nanoferrites insulating (3.23–3.57 eV). At higher frequencies, the impedance studies reveal minimal losses and better AC conductivity, pointing to improved dielectric characteristics. At higher frequencies, the Q-factor of La-doped calcium nanoferrites shows lower electromagnetic losses. The M–H curve exhibits ferromagnetic behavior, with La³⁺-doped calcium nanoferrites displaying a saturation magnetization ranging from 12.72 to 18.10 emu/g. The incorporation of La³⁺ also induces enhanced electrical polarization, leading to notable dielectric loss and increased absorption of electromagnetic waves. Consequently, these CaLa_xFe_2–xO₄ nanoferrites demonstrate potential as effective microwave absorbers across a wide frequency range, with significant shielding absorption observed at 8.8–9.1 GHz.