Seminars Archive

Physical properties of ion Implanted Mn Ge alloys

Abstract
The physical properties of Mn ion implanted Ge will be illustrated and reviewed showing results from a large variety of experients (X‿ray diffraction, Atomic Force Microscopy , Scanning Tunneling Microscopy and Spectroscopy, core level and valence band photoemission spectroscopy, Extended X‿ray absorption spectroscopy, SQUID, and magneto‿transport measurements) performed in the latest years and up to date. The Mn implantation, performed with a systematic variation of the substrate sample temperature during the implantation, gives rise to a rich variety of structural arrangements. Dilution, phase precipitation, formation of amorphous pockets, swelling of the implanted layer, or even total amorphization of the implanted layer, observed in differently prepared samples, are characterized by specific magnetic responses like room temperature ferromagnetism in a‿Mn‿Ge, or the occurrence of a metal‿insulator transition in c‿Ge with ferromagnetic Mn5Ge3 clusters inside. The magnetic properties are explained on the basis of the detailed knowledge of the various structural and electronic propertis of the Mn‿Ge alloys. References: 1) “Phase separation and dilution in ion implanted MnxGe(1‿x) alloys‿ L. Ottaviano, M. Passacantando, S. Picozzi, A. Continenza, R. Gunnella, A. Verna, G. Bihlmayer, G. Impellizzeri, and F. Priolo, Appl. Phys. Lett. 88, 061907 (2006). 2)‿Ferromagnetism in ion implanted amorphous and nanocrystalline MnxGe1−x‿ A. Verna, L. Ottaviano, M. Passacantando, S. Santucci, P. Picozzi, F. D’Orazio, and F. Lucari, M. De Biase, R. Gunnella, M. Berti, A. Gasparotto, G. Impellizzeri and F. Priolo, Phys. Rev. B 74, 085204 (2006). 3) “Direct structural evidences of Mn dilution in Ge‿ L. Ottaviano, M. Passacantando, A. Verna, R. Gunnella, E. Principi, A. Di Cicco, G. Impellizzeri and F. Priolo, J, of Appl. Phys. 100, 063528 (2006). 4) “Mn L2,3 X‿ray Absorption Spectra of a diluted Mn‿Ge alloy.‿ L. Ottaviano, M. Passacantando, A. Verna, F. D’Amico, and R. Gunnella, Appl. Phys. Lett. 90, 242105 (2007). 6) “Effects of dimensionality on spin dynamics of GeMn systems‿ O. Kazakova, R. Morgunov, J. Kulkarni, J. Holmes, and L. Ottaviano, Phys. Rev. B 77, 235317 (2008).