FERROMAGNETIC-RESONANCE DETERMINATION OF FCC-]HCP STRUCTURAL-CHANGE IN EPITAXIAL CO MN SUPERLATTICES/

A series of epitaxial [Co24 angstromMntMn]12 superlattices (3.2 angstr om less-than-or-equal-to t(Mn) less-than-or-equal-to 32 angstrom) was grown on hcp(0001) Ru buffer layers by ultrahigh vacuum e-beam evapora tion. Ferromagnetic resonance has shown that for samples with 3.2 angs trom less-than-or-equal-to t(Mn) less-than-or-equal-to 12 angstrom, th e cobalt layers are predominantly fcc and almost perfectly fcc for the sample having the thinnest Mn thickness [Co24 angstrom/Mn3.2 angstrom ]12. For samples with greater Mn thickness (t(Mn) > 12 angstrom), the cobalt layers are predominantly hcp with structural defects correspond ing either to large inclusions of fcc Co or stacking faults.