Structure and magnetic investigation of hard/soft Ba0.5Sr0.5Fe12O19/x(Ni0.5Zn0.5)Fe2O4 nanocomposite

Abstract

In this work, magnetic nanocomposites Ba0.5Sr0.5Fe12O19/x(Ni0.5Zn0.5)Fe2O4 with the compositions x = 10, 20, 30, and 50 wt%, arising from nickel-zinc ferrite added to barium strontium hexaferrite were prepared and characterized. The samples were synthesized using co-precipitation and ball milling methods. X-ray powder diffraction measurements validated the synthesis of nanocomposite with high purity and crystallinity. A transmission electron microscope was also used to analyze the morphology of the nanocomposites that demonstrated hexagonal platelet-like and spherical-like shapes for hard and soft phases, respectively. Also, multiple shapes of different grain sizes were formed, and their grain size decreased upon the addition of the soft phase. Besides, the elemental compositions and the oxidation states of (Ba2+, Sr2+, Ni2+, Ni3+, Zn2+, Fe2+, Fe3+and O2-) constituting the nanocomposites were investigated, using X-ray photoelectron spectroscopy. Additionally, the magnetic properties were examined using a vibrating sample magnetometer. According to Henkel plots, the existence of a weak exchange coupling interaction and the dominance of dipolar interactions were visible upon the addition of Ni0.5Zn0.5Fe2O4. Furthermore, the maximum energy product, (BH)max, is the energy density that a hard ferrite can store with low magnetic anisotropy. (BH)max of the nanocomposite containing 10 wt% of soft phase increased by 10% when compared to pure hard phase, reaching the highest value of (BH)max equal to 22.89 kJ/m3.