CRYSTALLOGRAPHY OF CO PT MULTILAYERS AND NANOSTRUCTURES/

Atomically engineered nanostructures and multilayers of Co/Pt exhibit strong perpendicular anisotropY. This unique property, that determines their potential as a magneto-optic recording medium, is dependent on a variety of microstructural parameters that include the overall cryst allography, thickness of the layers, orientation, defect formation, in terface reactions, etc. A series of Co/Pt multilayer samples with diff erent thickness of the Co layer were studied by electron diffraction. It has been determined that the Co layers persist in the fcc structure up to 50 angstrom thickness. As the thickness is varied from 3 to 50 angstrom in the multilayers, the Co film gradually relaxes to its bulk lattice parameter. (111) twinning and lattice strain at the interface s between Pt and Co layers are also observed. The symmetry-forbidden r eflections observed at -1/3{224} positions in [111] zone diffraction p atterns of the multilayer are due to (111) twinning and compositional modulations along the multilayer growth direction.