Eur. Phys. J. B 48, 449-462 (2005)
https://doi.org/10.1140/epjb/e2006-00012-6

Ion-beam induced changes in magnetic and microstructural properties of thin iron films

II. Physikalisches Institut and Sonderforschungsbereich 602, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany

Corresponding author: ^a plieb@gwdg.de

Received: 8 July 2005
Revised: 20 October 2005
Published online: 19 January 2006

Abstract

Changes in magnetic and structural properties of 60–82 nm iron films induced by heavy-ion implantation were studied using the magneto-optical Kerr effect, Mössbauer spectroscopy, Rutherford backscattering spectroscopy, X-ray diffraction, and X-ray absorption fine structure. The influence of ion-beam parameters (ion mass, fluence) and of sample parameters (external magnetic field and stress during implantation) were investigated. The Fe films, some of them containing a thin ⁵⁷Fe marker layer for Mössbauer spectroscopy, were deposited on Si(100) substrates, by electron-beam and effusion-cell evaporation. The films were irradiated with ²⁰Ne, ⁵⁶Fe, ⁸⁶Kr and ¹³²Xe ions at energies chosen so that the implantation profiles peaked near the middle of the Fe films. The as-deposited films were magnetically isotropic and had a high coercivity. After ion implantation, the coercivity decreased and magnetic anisotropy developed. Both changes correlated with a decrease in the internal film stress. External mechanical stress applied during the irradiation had hardly any influence on the magnetic texture, opposite to an external magnetic field applied during or before ion implantation. The results are compared with those obtained for ion-irradiated polycrystalline Ni films and epitaxial Fe films and discussed with respect to the role of radiation-induced extended defects as pinning centers.