Microstructure and Magnetic Properties of FePt Thin Films on SiO2/Si (100) and Si Substrates Prepared Under External Magnetic Field

Abstract

FePt thin films were prepared by pulsed laser deposition (PLD) on SiO2/Si (100) and Si (100) singlecrystal substrates at different temperatures of 600, 700 and 800∘C. In all samples, the external magnetic field produced by a permanent magnet has been used to improve and control the intensity of the laser plume. X-ray diffraction analysis showed that the L1 crystal structure was created and the long-range order parameter increased from near 0.6 to a maximum of 0.98 in films grown at 800∘C for two types of films. The increasing of stress in FePt/Si (100) thin films due to the lattice mismatch leads to the change of surface morphology from the island-like mode with grain separation to interconnected grains that have a tendency to grow in a specific direction. Moreover, the roughness of the surface increased by increasing the lattice mismatch and temperature. In addition, the maximum value (over 9400 Oe) of coercivity was obtained by increasing the temperature to 800∘C using SiO2/Si (100) substrate. All series of films grown on SiO2/Si (100) show a large K u of 10.2×107 erg/cm3at the temperature of 800∘C.