Structural and magnetic properties of hard-soft BaFe 12 O 19 /(Zn 0.5 Co 0.5 )Fe 2 O 4 ferrites.

Hard-soft nnanocomposites of (1-x) BaFe12O19/(Zn0.5Co0.5)Fe2O4, for x=0.00, 0.25, 0.50, 0.75 and 1.00, were prepared via co-precipitation and high-speed ball milling techniques, respectively. The synthesized samples were characterized via X-ray diffraction (XRD), transmission electron microscope (TEM), Fourrier Transform Infrared (FTIR) and vibrating sample magnetometer (VSM). XRD revealed the formation of hard-soft nanocomposites. TEM indicated that the two phases are well distributed and the particle size distribution is narrower for low content of soft phase, leading to better exchange coupling between the grains. Magnetic measurements were performed at 300 K and 77 K. The results showed a good single-phase magnetic behaviour, verifying the good exchange coupling between hard and soft phases. For low (Zn0.5Co0.5)Fe2O4content, the dipolar interactions were dominated by the exchange-coupling interactions. Additionally, the optimum values of saturation and remanent magnetizations, coercivity, and squareness ratio were obtained for x=0.5. This was attributed to the dominance of exchange-coupling interaction. The enhancement of magnetic properties and energy product (BH)maxfor nanocomposites at low temperature is skilled to the reduction in the thermal fluxes of magnetic moments at the surface. The maximum energy product (BH)maxwas observed in C2 at both temperatures with a smaller value than that of pure BaFe12O19.