Arrangement of rare-earth elements at prismatic grain boundaries in silicon nitride

The arrangement of rare-earth atoms at {100} prism planes of La- and
Lu-containing polycrystalline Si3N4 specimens is studied using
high-angle annular dark-field scanning transmission electron
microscopy. For both systems, the attachment sites of rare-earth atoms
are well-defined and largely conform to the periodicity of the
terminating plane of the Si3N4 grain. We observe significant
differences between the structural arrangement of La and Lu atoms at
the interface.