Impact of sonication time on the structural and magnetic features of CoFe2O4/Ni0.8Cu0.1Zn0.1Fe2O4 hard-soft nanocomposites

Abstract

Hard/soft (H/S) CoFe2O4/Ni0.8Cu0.1Zn0.1Fe2O4 nanocomposites (NCs) were prepared via ultrasonic irradiation method under different ultrasonication durations (10, 20, 30, 40, 50, and 60 min). The structure and morphology of these nanocomposites were analyzed through XRD, FT-IR, SEM, TEM, and EDX techniques, which confirmed the successful preparation of the desired nanocomposites. The crystallites/particles size was found to reduce with increasing ultrasonication duration. The magnetic properties of H/S CoFe2O4/Ni0.8Cu0.1Zn0.1Fe2O4 NCs prepared via ultrasonication method under different ultrasonication durations (10, 20, 30, 40, 50, and 60 min) were investigated through measurements of magnetization against the magnetic field (M-H) at 10 and 300 K. The soft character of the prepared NCs at room temperature depicted their superparamagnetic behaviors. At extremely low temperatures (T = 10 K), all H/S ferrite NCs revealed opened M-H hysteresis loops, indicating their ferrimagnetic behavior at low temperatures. All H/S NCs do not reveal any kind of anomalies in their M-H curves. Additionally, the SFD (switching field distribution) analysis pointed out a single peak in dM/dH against H curves. It was found that the intergranular exchange coupling interactions are more dominant than the intergranular dipolar interactions. Such a result indicates that the current synthesis method is useful to produce good exchange-coupled hard/soft ferrite NCs. It was also observed that the Ms and Mr values at both 10 and 300 K are decreasing with rising the ultrasonication duration. However, the Hc value was found to increase with rising ultrasonication duration, reaching a maximum value under an ultrasonication duration of 30 min, then, the Hc value decreases with further rising the ultrasonication duration. The plausible reasons for the variations in magnetic parameters were discussed.