Structural, magnetic, optical properties and cation distribution of nanosized CoZnTmFeO (0.0 ≤ x ≤ 0.04) spinel ferrites synthesized by ultrasonic irradiation.

This study expressed the influence of Tm substitution on the structural, optical and magnetic properties of Co-Zn spinel ferrites (CoZnTmFeO (0.0 ≤ x ≤ 0.04)). The different compositions were synthesized by sonochemical method using Qsonica ultrasonic homogenizer, frequency: 20 kHz and power: 70 W for 60 min. XRD patterns proved the presence of single-phase spinel ferrites with crystallites size in the 8-10 nm range. Cation distribution approved the occupancy of octahedral (B) site by Tm. The morphology and the elements stoichiometry are obtainable through FE-SEM, EDX and elemental mapping. Optical band gap (E) values were estimated via DR % (percent diffuse reflectance) investigations and Kubelka-Munk theory. Tauc plots revealed that direct E values are ranging between 1.49 and 1.68 eV. The analyses of magnetization versus magnetic field, M(H), were performed. The following magnetic parameters like saturation magnetization M, squareness ratio (SQR = M/M), magnetic moment n, coercivity H and remanence M have been evaluated. M(H) curves revealed the superparamagnetic (SP) at RT and ferromagnetic property at 10 K. It was showed that the Tm substitutions significantly affect the magnetic properties of host spinel ferrites. An increasing trend in the M, M, H, and n values was noticed for lower Tm substitution content.