INFLUENCE OF AL CAPPING LAYERS ON GROWTH, TOPOGRAPHY, AND MAGNETIC-PROPERTIES ON MNBI THIN-FILMS

Bi/Mn bilayers have been deposited on fused-quartz substrates at room temperature and annealed at elevated temperatures of 300-380 degrees C . To investigate the influence of capping layers on MnBi crystallite s ize and magnetic properties; some of the Bi/Mn bilayers were protected by Al and SiOx layers. The coercive fields of the resulting MnBi film s without a protective layer reach values of up to 1.25 T. In case of depositing an Al capping layers prior to annealing, the coercive field s are decreasing strongly showing coercive fields in the range of 0.6 T In contrast, using SiOx as a capping layer, the Ken: hysteresis loop s show a nonlinearity near the coercive field indicating an inhomogene ous film. The change in the coercive field is explained by the influen ce of capping layers on the MnBi crystallite size during annealing. (C ) 1996 American Institute of Physics.