Abstract
•Spinel nanoferrites (SNFs) were fabricated successfully via Ultrasonic irradiation.•XRD presented the creation of Mn-Zn ferrite.•It exhibited the superparamagnetic (SPM).•At lower temperatures illustrated ferrimagnetic (FM).
Mn0.5Zn0.5ErxDyxFe2-2xO4 (x ≤ 0.1) spinel nanoferrites (SNFs) were fabricated successfully via Ultrasonic irradiation. Structural and morphological analysis were investigated via X-ray diffraction diffractometer (XRD), scanning (SEM) and transmission electron microscopes (TEM), Fourier-transform infrared spectroscopy (FTIR), and Surface Area Analyzers (BET). XRD showed the formation of highly pure Mn-Zn spinel ferrite phase with an average crystallite size within 19–26 nm range. The formation of spherical nanoparticles with small particles size was also approved by SEM and TEM techniques. Magnetization response to the magnetic field applied (M vs H) and temperature and (M vs T under ZFC and FC modes), were investigated to understand the impact of Er and Dy co-doping mechanism on the magnetic features of MnZn SNFs. The findings through the magnetization measurements demonstrate superparamagnetic (SPM) behavior with single magnetic domain particles for different prepared products and with no coercivity (Hc) and remanence (Mr) at RT and at temperatures above the TB (blocking temperature). At lower temperatures below TB, it has been illustrated that the prepared SNFs have ferrimagnetic (FM) behavior with the existence of coercivity (Hc) and remanence (Mr). The calculated squareness (SQR = Mr/Ms) at T = 10 K are ranging between 0.14 and 0.29, which are below the predicted value of 0.5, reflecting the MMD nature in different prepared SFNPs at T = 10 K. In comparison to pristine product, the saturation magnetization (Ms) initially increased for lower co-doping contents of Er and Dy up to x = 0.04 and then decreased by the further Er and Dy co-doping concentrations (x > 0.04).