On the Crystal Structure of Fe6Ge5and Its Relationship toB8-Type Structures

Abstract

Epitaxial intergrowths of Fe6Ge5andB8-type Fe1+xGe was investigated by means of electron diffraction. A crystal structure description of Fe6Ge5in terms ofB8- andB1-type structures was established; 4/5 of the Ge atoms in Fe6Ge5can be described with one-octahedron wide slabs of hexagonal close-packed Ge atoms with all octahedral sites and 1/2 of the trigonal bipyramidal sites therein filled with Fe atoms (B8). Additionally, all Ge atoms can be described by a two-octahedra wide slab of cubic close-packed Ge atoms with 4/6 of the octahedral sites filled with Fe atoms and 1/6 of the octahedral sites filled withtwoFe atoms, one in each square pyramid (B1). At the surface interconnecting these slabs, octahedra from theB8 andB1 slabs share faces and the trigonal bipyramid from the hcp array and two edge-sharing tetrahedra from the ccp array are merged to form a pentagonal bipyramid. Show more