Fabrication and Magnetic Properties of Fe Thin Films on a Substrate Excited by SAW

Fe films of thickness 300Å were prepared by electron beam evaporation and dc magnetron sputtering onto LiNbO3 single-crystal substrate excited by surface acoustic waves (SAWs) at 45 MHz. A biaxial anisotropy was induced in the film plane for evaporated films with the substrate excited at 8 V, but was not induced at all in sputtered films. The saturation magnetization Ms of the evaporated films increased with increasing excitation voltage, and reached the bulk value at an excitation voltage of 8 V. However, the Ms of sputtered films was not changed by SAW excitation. The density of evaporated films was close to the density of bulk Fe at an excitation voltage of 8 V. This fact shows that the structure of evaporated films changed from a porous to a dense structure with SAW excitation. Further, the film surface became smooth when the substrate was excited.