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Abstract: Strontium ferrite (SrM) thin films on Au nano-dots were deposited on single-crystal sapphire with (00 l) orientation (Al2O3 (00 l)), single crystal MgO with (111) orientation (MgO (111)) and Corning glass by employing dc magnetron sputtering system. In order to improve the crystalline orientation for Au nano-dots, an attempt to use the single crystal as the substrate has been carried out. The effects of the substrates and underlayer on grain orientation, magnetic properties, and microstructure of SrM thin films were studied. The SrM grows with its c-axis oriented perpendicularly to the film. The maximum of coercivity and remanent squareness ratio in perpendicular direction for single crystal Al2O3 (00 l) substrate is 3.0kOe and 0.51, respectively. It is found that the magnetic interaction between SrM grains deposited on Au nano-dots is less than that for the continuous film. [Copyright &y& Elsevier]

Highlights: [•] Co2+ substituted lithium ferrite. [•] Structure changes from order to disorder. [•] Coercivity increased with Co2+ substitution. [•] Blocking temperature increased whereas Curie temperature decreased with Co2+ substitution. [Copyright &y& Elsevier]

Abstract: The Cu x Mg0.5−x Zn0.5Fe2O4 (x =0, 0.1, 0.2, 0.3, 0.4 and 0.5) ferrites were prepared by sol–gel method. The effect of copper content on the structural and magnetic properties was investigated by X-ray diffraction (XRD), Mössbauer spectroscopy (MS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and magnetic susceptometer. Results show that single spinel ferrite particles were prepared by controlling the type and amount of additive. Copper content has significant influence on magnetic properties of prepared samples. It was found that with increasing copper in Cu x Mg0.5−x Zn0.5Fe2O4, saturation magnetizations along with grain size were increased while the values of coercivity were decreased. The variation of effective magnetic susceptibility exhibits almost linear trend with magnetic field. A frequency-dependence peak was observed in ac magnetic susceptibility versus temperature for fine particles which is well fitted by Vogel–Fulcher model. It was proved that there is strong magnetic interaction among prepared nanoparticles. [ABSTRACT FROM AUTHOR]