Fe+ ion irradiation induced changes in structural and magnetic properties of iron films

• Published in: Nuclear materials and energy 2016-12, Vol.9 (C), p.459-464
• Main Authors: Papamihail, K., Mergia, K., Ott, F., Serruys, Yves, Speliotis, Th, Apostolopoulos, G., Messoloras, S.
• Format: Article
• Language: English
• Subjects: Grain size; Implantation; Ion irradiation; Iron; Magnetism; Polarized neutron reflectivity
• ISSN: 2352-1791; 2352-1791
• DOI: 10.1016/j.nme.2016.03.006

490keV Fe+ ion irradiation of Fe films•Increases the Fe magnetic moment from that of the bulk and to a depth within the film (top sublayer) comparable to that in which the damage from primary knock-ons prevail•Reduces the Fe magnetic moment below the top sublayer and in depths in which implantation prevails (bottom sublayer) and•The top Fe sublayer magnetic moment increases with dose exhibiting a maximum at 96 dpa and then decreases whereas the opposite is observed for the bottom sublayer. 490keV Fe+ ion irradiation of 200nm thick Fe films was found to induce both structural and magnetic changes. Both, the lattice constant and the grain size increase as a function of dose and both properties follow the same power law. Irradiation induces a depth dependent magnetic profile consisting of two sublayers. The top Fe sublayer has a magnetic moment higher than that of the Fe before the irradiation whereas the bottom sublayer lower. The two sublayers are connected with the effects of Fe+ irradiation, i.e. the top sublayer with the depth in which mainly radiation damage occurs whereas the bottom one with the implantation of impinging Fe+ ions. The magnetic moments of the two sublayers have a non-monotonous variation with irradiation dose depicting a maximum for the top sublayer and a minimum for the bottom one at 96.2 dpa (‘displacements per atom’). The magnetic moment enhancement/reduction is discussed in relation with the atomic volume variation in the case of atom displacements and/or implantation effects.