Structure and magnetic properties of epitaxial Fe films on GaAs(100) and InAs(100)

Single crystal BCC Fe films have been stabilized on both GaAs(1 0 0)-4 x 6 and InAs(1 0 0)-4 x 2 substrates at room growth temperature. The magnetic p roperties of the Fe/GaAs were found to proceed via three phases determined by the growth morphology; a non-magnetic phase, a short-range-ordered super paramagnetic phase and a ferromagnetic phase above about five monolayers. A uniaxial magnetic anisotropy (UMA) was observed in ultrathin Fe/InAs(1 0 0 )-4 x 2 films within a narrow thickness range of about 5-10ML. The easy axi s is along the [0 1 1] direction rather than [0 (1) over bar 1], the easy a xis in Fe/GaAs(1 0 0)-4 x 6 and 4 x 2. As ultrathin Fe films tend to be com pressed in-plane on GaAs and expanded on InAs, the strikingly different ani sotropy behaviour in the Fe/GaAs(1 0 0) and the Fe/InAs(1 0 0) may indicate the importance of magneto-elastic interactions. (C) 1999 Elsevier Science B.V. All rights: reserved.