Abstract
This paper focused on the structure, optic and magnetic properties of niobium substituted Co0.5Mn0.5Fe2-xO4 nanoparticles (NPs) that synthesized by hydrothermal method. The synthesis of cubic spinel ferrite structures was confirmed via XRD, SEM along with EDX and elemental mapping, TEM and FT-IR. The crystallite size of the products was found between 17 and 18 nm. The %DR-UV-visible spectrophotometer revealed that the band gap values are 0.37, 0.52, 0.54, and 0.46 eV for each substitution respectively. Room temperature (RT) and 10 K magnetization measurements were performed on spinel Co0.5Mn0.5Fe2-xO4 (0.00 <= x <= 0.10) NPs by VSM. The specific magnetic parameters such as saturation magnetization (M-s), remanence (M-r), coercivity (H-C), magnetic moment (n(B)) and squareness ratio (SQR = M-r/M-s) were determined and evaluated. The M(H) curves showed ferrimagnetic nature at RT and 10 K. The Nb3+ ion substitution significantly improves the magnetizations data. An enhancement in the M-s, M-r, and n(B) values was observed in substituted products compared to pristine one. The highest values were obtained for x = 0.04 product. The obtained magnetic data are primarily derived from the substitution of Fe3+ ions with Nb3+ ions that will strengthen the super-exchange interactions. (C) 2019 Elsevier B.V. All rights reserved.