Preparation and magnetic properties of different morphology nano-SrFe12O19 particles prepared by sol–gel method

First a precursor gel was prepared using the sol–gel method, KCl, KBr or KI was respectively mixed into dry-gel according to the mass ratio of dry-gel to salt of 1:3. The mixture of KCl and dry-gel was calcined at 850 °C for 2 h to obtain the needle-like nano-SrFe12O19. The rod-like and bubble nano-SrFe12O19 was respectively prepared by calcining the mixture of KBr and dry-gel or KI and dry-gel, and spherical nano-SrFe12O19 was prepared only by calcined dry-gel. The morphology and grain size of nano-SrFe12O19 were determined by transmission electron microscopy (TEM). The result of X-ray diffraction (XRD) and infrared spectrum (IR) showed that the sample prepared by adding or not adding salt is pure strontium ferrite particles. The maximum coercivity and the saturation magnetization of the strontium ferrite powder were determined by vibrating sample magnetometer (VSM). The relation between morphology and magnetic properties and mechanism of influence of the template agent on the morphology of nano-SrFe12O19 was studied in this work.