Effect of Nb substitution on magneto-optical properties of Co0.5Mn0.5Fe2O4 nanoparticles

Abstract This paper focused on the structure, optic and magnetic properties of niobium substituted Co 0.5 Mn 0.5 Nb x Fe 2-x O 4 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 Co 0.5 Mn 0.5 Fe 2-x Nb x O 4 (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 Nb 3+ 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 Fe 3+ ions with Nb 3+ ions that will strengthen the super-exchange interactions.