Structural, Magnetic, and Mossbauer Parameters' Evaluation of Sonochemically Synthesized Rare Earth Er3+ and Y3+ Ions-Substituted Manganese-Zinc Nanospinel Ferrites.

The effect of Er3+ and Y3+ ion-co-substituted Mn0.5Zn0.5Er x Y x Fe2-2x O4 (MZErYF) (x ≤ 0.10) spinel nanoferrites (SNFs) prepared by a sonochemical approach was investigated. Surface and phase analyses were carried out using SEM, TEM, and XRD. Hyperfine parameters were determined by fitting room-temperature (RT) Mossbauer spectra. Magnetic field-dependent magnetization data unveiled the superparamagnetic nature at RT and ferrimagnetic nature at 10 K. RT saturation magnetization (M S) and calculated magnetic moments (n B) are 34.84 emu/g and 1.47 μB, respectively, and have indirect proportionalities with increasing ion content. M S and n B data have a similar trend at 10 K including remanent magnetizations (M r). The measured coercivities (H C) are between 250 and 415 Oe. The calculated squareness ratios are in the range of 0.152-0.321 for NPs and assign the multidomain nature for NPs at 10 K. The extracted effective magnetocrystalline constants (K eff) have an order of 104 erg/g except for Mn0.5Zn0.5Er0.10Y0.10Fe1.80O4 SNFs that has 3.37 × 105 erg/g. This sample exhibits the greatest magnetic hardness with the largest magnitude of H C = 415 Oe and an internal anisotropy field H a = 1288 Oe among all magnetically soft NPs.