Role of composition and grain size in controlling the structure sensitive magnetic properties of Sm3+ substituted nanocrystalline Co-Zn ferrites

The nanocrystalline samarium substituted Co-Zn ferrites with chemical formula Co0.7Zn0.3SmyFe2-yO4 (where y = 0, 0.01, 0.02, 0.03, 0.04) were synthesized by sol-gel autocombustion route. The analysis of X-ray diffractograms (XRD) reveals the formation of cubic spinel structure. The planes indexed from XRD analyses were confirmed in the selected area electron diffraction (SAED) image of the sample. Nano-crystalline nature of the particles in the ferrite samples was confirmed by TEM. The morphology was analyzed by scanning electron microscopy (SEM). Magnetic measurements show an increase in the magnetization for x < 0.03. The decrease in magnetization due to spin canting is observed for x <= 0.04. The coercivity depends on Sm3+ doping concentration, grain size and saturation magnetization. The complex permeability of the ferrites was analyzed as the function of frequency and Sm3+ composition (y). The real part of complex permeability varies linearly with the grain size. (C) 2020 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.