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

The effect of Er and Y ion-co-substituted MnZnEr Y Fe O (MZErYF) ( ≤ 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 ( ) and calculated magnetic moments ( ) are 34.84 emu/g and 1.47 μ, respectively, and have indirect proportionalities with increasing ion content. and data have a similar trend at 10 K including remanent magnetizations ( ). The measured coercivities ( ) 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 ( ) have an order of 10 erg/g except for MnZnErYFeO SNFs that has 3.37 × 10 erg/g. This sample exhibits the greatest magnetic hardness with the largest magnitude of = 415 Oe and an internal anisotropy field = 1288 Oe among all magnetically soft NPs.