Fabrication, crystallographic and magnetic properties of SrM perpendicular films on Au nano-dot arrays

Strontium ferrite (SrM) thin films on Au nano-dots were deposited on single-crystal sapphire with (0 0 l) orientation (Al2O3 (0 0 l)), single crystal MgO with (1 1 1) orientation (MgO (1 1 1)) 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 (0 0 l) substrate is 3.0 kOe 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.