Focused ion beam was utilized to locally modify magnetism and structure of L10 FePt perpendicular thin films. As a first step, we have performed a magnetic, morphological, and structural study of completely irradiated FePt films with different Ga+ doses 1x10^13 – 4x10^16 ions/cm2 and ion beam energy of 30 keV. For doses of 1x10^14 ions/cm2 and above a complete transition from the ordered L10 to the disordered A1 phase was found to occur, resulting in a drop of magnetic anisotropy and in the consequent moment reorientation from out-of-plane to in-plane. The lowest effective dose in disordering the structure 1 10^14 ions/cm2 was found not to affect the film morphology. Taking advantage of these results, continuous two-dimensional 2D patterns of perpendicular magnetic structures 250 nm dots, 1 micron dots, 1 micron-large stripes were produced by focused ion beam without affecting the morphology. The 2D patterns were revealed by means of magnetic force microscopy, that evidenced peculiar domain structures in the case of 1 micron dots.
Local modification of magnetism and structure in FePt (001) epitaxial thin films by focused ion beam: Two-dimensional perpendicular patterns
VAVASSORI, Paolo;
2008
Abstract
Focused ion beam was utilized to locally modify magnetism and structure of L10 FePt perpendicular thin films. As a first step, we have performed a magnetic, morphological, and structural study of completely irradiated FePt films with different Ga+ doses 1x10^13 – 4x10^16 ions/cm2 and ion beam energy of 30 keV. For doses of 1x10^14 ions/cm2 and above a complete transition from the ordered L10 to the disordered A1 phase was found to occur, resulting in a drop of magnetic anisotropy and in the consequent moment reorientation from out-of-plane to in-plane. The lowest effective dose in disordering the structure 1 10^14 ions/cm2 was found not to affect the film morphology. Taking advantage of these results, continuous two-dimensional 2D patterns of perpendicular magnetic structures 250 nm dots, 1 micron dots, 1 micron-large stripes were produced by focused ion beam without affecting the morphology. The 2D patterns were revealed by means of magnetic force microscopy, that evidenced peculiar domain structures in the case of 1 micron dots.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
