Evidence of a ternary Co1-xFexSi2 phase with a CaF2-type structure: High-resolution transmission electron microscopy and diffraction anomalous fine structure study

摘要

A ternary silicide phase (Co0.6Fe0.4Si2) with a cubic CaF2-type structure, grown in epitaxy on Si(111), is investigated by using diffraction anomalous fine structure and high-resolution transmission electron microscopy. This cubic phase is formed by annealing at 930 K a room-temperature-grown epitaxial ternary layer with ratios of 0.7:2 for Fe:Si and 0.3:2 for Co:Si. This phase is mixed with a tetragonal alpha-FeSi2-type phase, but both phases are ternary. It is shown that a large amount of Fe (about 40) substitutes for Co atoms on the metallic sites of the CaF2-type lattice of the cubic silicide phase. (C) 2002 American Institute of Physics. References: 16