Tailored magnetic properties of Sm(Zn) substituted nanocrystalline barium hexaferrites

Abstract: Sm and SmZn substituted nanocrystalline barium hexaferrites (Ba1−x Sm x Fe12O19 and Ba1−x Sm x Fe12−x Zn x O19, x =0–0.6) were prepared by the sol–gel autocombustion process. X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) were used to characterize the phase composition, crystal structure and magnetic properties of the as-prepared barium hexaferrites. All results indicated that the substitution content (x) critically influenced on the phase composition and magnetic properties. When the substitution content x >0.2, impurity phases such as α-Fe2O3, SmFeO3 and ZnFe2O4 were detected, which diluted and weakened saturation magnetization (M s). For the Sm-doped samples, owing to the hyperfine field, canting spin, magnetic dilution and impurity phases, M s increased with x firstly, and then decreased when x >0.03. On the other hand, the coercivity (Hc) continuously increased with x. Nevertheless, for the SmZn-doped samples, M s reached maximum when x =0.06 and Hc almost unchanged with x. Compared the magnetic properties of Sm- and SmZn-doped samples, it was proved that Zn2+ substituted Fe3+ at 4f 2 sites and Sm3+ substituted Ba2+, which changed Fe3+ to Fe2+ at 2a sites in order to satisfy the electroneutrality principle. [Copyright &y& Elsevier]