Magnetic, structural, optical band alignment and conductive analysis of graphene-based REs (Yb, Gd, and Sm) doped NiFe2O4 nanocomposites for emerging technological applications

Abstract

The productive and straightforward strategy was developed to fabricate graphene based NiFe2O4 doped rare-earth (RE) ions nanocomposites for enhancing the magnetic and structural characteristics of ferrites. RE nanoparticles (NPs) such as Yb3+, Gd3+ and Sm3+ were doped in NiFe2O4 ferrite structure via sol-gel auto-combustion method and hydrothermal method was utilized to fabricate their graphene-based nanocomposites. The weight loss and decomposition of the nanocomposites were determined using temperature-dependent thermo gravimetric analysis (TGA/DTA). The single-phase structure of the NiFe2O4, NiFe2O4/G, Yb doped NiFe2O4/G, Gd doped NiFe2O4/G, and Sm doped NiFe2O4/G nanocomposites was confirmed through XRD. The morphological analysis was evaluated using FESEM. The higher and lower frequency bands exist between 680 and 750 cm−1 and 415–510 cm−1 confirm the spinel phase of the nanocomposites. The optical band gap for NiFe2O4, NiFe2O4/G, Yb doped NiFe2O4/G, Gd doped NiFe2O4/G, and Sm doped NiFe2O4/G nanocomposites was changed from 2.66 to 1.65 eV respectively. The increasing trend in magnetic saturation (11.552 emu/g - 46.243 emu/g) was noticed in the spinels through the substitution of rare-earth elements including Yb3+, Gd3+ and Sm3+. DC conductivity was in the range of 1.75 × 10−3 to 4.24 × 10−3 S cm−1. The activation energy in the paramagnetic region is 0.0171–0.1890.