STRUCTURE, MAGNETIC, AND MAGNETOOPTICAL PROPERTIES OF MNBI FILMS GROWN ON QUARTZ AND (001) GAAS SUBSTRATES

MnBi films are prepared on quartz and on (001) orientated GaAs substra tes by molecular beam epitaxy in ultrahigh vacuum environment. Both ki nds of substrates are used simultaneously. The influence of the substr ate material is investigated with respect to the structural, the magne tic, and magneto-optical properties of the MnBi films. By evaporating a 100 nm thick SiOx buffer layer the homogeneity of the composition is improved and a grain size of about 100 nm is achieved without adding other elements. In contrast to previous investigations, our measured m agneto-optical Kerr rotation spectra show no Kerr rotation peak near 3 .35 eV. These results confirm theoretical predictions whereupon this p eak is attributed to oxygen which occupies interstitial sites in the r egular MnBi lattice. (C) 1998 American Institute of Physics. [S0021-89 79(98)03919-X].