Synthesis,structural and microwave absorption properties of Cr-doped zinc lanthanum nanoferrites Zn1-xCrxLa0.1Fe1.9O4 (x=0.09, 0.18, 0.27 and 0.36)

Cr-doped zinc-lanthanum nanoferrites Zn_1-xCr_xLa_0.1Fe_1.9O₄ (x = 0.09, 0.18, 0.27, and 0.36) were successfully synthesized using sonochemical reactors. Effect of powder production parameters were extensively studied and powder characterization was performed. Existence of cubic spinel structures in the prepared nanoferrites with the average crystallite size ranging from 35 to 51 nm was confirmed by X-ray diffraction studies. An electrochemical impedance analyzer was used to measure the dielectric constant (ε′), loss tangent (tan δ), and complex dielectric constant (ε") with respect to frequency and composition ratio. Maxwell–Wagner polarization and hopping mechanism were calculated to distinguish the variations in ε′, tan δ, and ε". The Nyquist impedance plots for nanoferrites revealed the pseudocapacitance as well as resistive behavior. Vibrating sample magnetometer studies reveled the ferromagnetic behavior of nanoferrites. Substantially increased saturation magnetization and decreased coercivity were noted with respect to increased Cr²⁺ ions in the prepared nanoferrites. It was found that the addition of chromium in Zn_1-xCr_xLa_0.1Fe_1.9O₄ nanoferrites enhances the optical, electrical, and magnetic properties of the nanoferrites.