Growth of ultrathin Fe films on Ge(100): Structure and magnetic properties

      P. Ma 
      Department of Physics, University of Western Ontario, London, Ontario, Canada N6A 3K7

      P. R. Norton 
      Department of Chemistry, University of Western Ontario, London, Ontario, Canada N6A 5B7

Received 7 April 1997; revised 25 June 1997

The structure and magnetic properties of ultrathin Fe films grown on Ge(100) at room temperature have been studied by low-energy electron diffraction, Auger electron spectroscopy (AES),
angle-resolved AES, and in situ magneto-optical Kerr effect (MOKE) measurements. Fe initially grows on Ge(100) in a disordered fashion, with local order commencing around 4 ML. The film
grows with a bcc structure for thicknesses greater than 7 ML. Our data are consistent with 6% Ge intermixed in the films. Significant intermixing starts at about 160 °C, with rapid diffusion of Fe into
the bulk occurring at temperatures higher than 400 °C. A single-loop to stepped-loop to single-loop sequence of ferromagnetic loops was observed by MOKE measurements. Hysteresis loop
simulations were performed based on the coherent model, the results suggesting that strong in-plane uniaxial anisotropy exists in these films, especially for very thin films. The sequence of loops is due
to the increase of the ratio between the cubic anisotropy and the uniaxial anisotropy as the film thickness increases.

©1997 The American Physical Society

URL: http://publish.aps.org/abstract/PRB/v56/p9881
PACS: 68.55.-a, 75.70.Ak, 81.15.-z, 75.30.Gw