MAGNETOOPTICAL PROPERTIES OF MNBI1-XSBX FILMS

We have grown MnBi1-xSbx alloy films on mica and glass substrates unde r UHV conditions, and performed a systematic study of the structural, magnetic and magneto-optic properties on films in the concentration ra nge 0 less than or equal to x less than or equal to 0.4. Sharp Reflect ion High Energy Electron Diffraction (RHEED) patterns were observed fo r samples grown on mica substrates, indicating epitaxial growth. X-ray diffraction patterns of MnBi1-xSbx grown on glass substrates show the se films to be highly textured, with the c-axis parallel to the substr ate normal. We found that only samples with Mn concentration above 50 at. % exhibited good magneto-optical properties. Perpendicular magneti zation and Kerr rotation larger than 0.5 degrees were observed for sam ples with Sb concentration less than 8 at. % in mica and 4 at. % on gl ass. For larger concentrations of Sb, the coercivity increased rapidly while Kerr rotation decreased. Samples grown on both types of substra tes showed an increase in the Kerr rotation and ellipticity with decre asing light wavelengths. The off-diagonal E-field reflectivity, r(xy), which describes the magneto-optic efficiency of the sample, is larger than that reported for TbFeCo layers.