Microwave absorbing material of cobalt lanthanum ferrite: the contributions of intrinsic and extrinsic factors on the microwave absorption properties

Microwave absorbing materials are greatly influenced by intrinsic and extrinsic factors. These two factors have been explored in an integrated manner so that it is hoped that they will be able to provide a comprehensive picture regarding microwave absorption.The present study have been investigated the magnetic and microwave absorption properties of cobalt lanthanum ferrite (CoLa_xFe_(2-x)O₄) with varying concentrations of lanthanum (x = 0.00; 0.01; 0.03 and 0.05). The samples were synthesized by using the solid-state reaction method. The characterization of material properties was conducted utilizing a suite of analytical techniques, including X-ray diffractometer (XRD), fourier transforms infrared spectroscopy (FTIR), scanning electron microscope (SEM), vibrating sample magnetometer (VSM), and vector network analyzer (VNA). Intrinsic factors are intrinsic characteristics of materials which include physical and chemical parameters, magnetic properties and resonance frequencies, while extrinsic factors are material geometry factors which include morphology, shape and particle size. The XRD analysis reveals that all the samples exhibit a single phase of CoFe₂O₄ at this particular stage. The observed crystal structure is refined by a cubic spinel arrangement belonging to the F d-3 m space group. The presence of the spinel phase was confirmed through the analysis of FTIR spectra, which exhibited two distinct frequencies at 593 cm⁻¹ and 403 cm⁻¹. These findings support the existence of Fe³⁺ ions that occupy the A (tetrahedral) and B (octahedral) positions within the spinel lattice. The SEM image of the CoLa_xFe_(2-x)O₄ samples exhibit a uniform shape of cubic, with the particle size of the doped sample appears smaller than the undoped samples. The results of the magnetic properties measurement indicate a drop in the saturation magnetization (M_s) values and an increase in the coercive field (H_c) values. The microwave absorption characteristics of the CoLa_xFe_(2-x)O₄ (x = 0.00; 0.01; 0.03 and 0.05) series, were assessed within the X-band frequency range (8–12 GHz). The study's findings indicate that substituting La³⁺ ions resulted in an enhancement of the microwave absorption capability in terms of intrinsic and extrinsic factors.