Simultaneous laser-magnetic field treatment of SrFe12O19 thin films grown by pulsed laser deposition

Strontium hexaferrite (SrFe12O19) thin films were grown by pulsed laser deposition on (0 0 0 1) single crystal sapphire substrates at substrate temperatures of 600 and 800 °C. Post-deposition Nd:YAG laser annealing with external magnetic field was applied. The films deposited at the higher substrate temperature were c-axis textured. Very high squareness (≈1) of the hysteresis loops was obtained for the films deposited at the lower temperature. The laser modification of the ferrite thin films produced a smooth film surface and higher coercive forces, particularly in the direction of applying the external magnetic field. The annealed films showed significant improvement of the perpendicular coercive force. The higher magnetization of the films is a result of the c-axis crystal orientation and formation of grain chains in the films.