Observations of Sub‐Unit‐Cell Stacking Elements in Mixed‐Layer Structures by Electron Microscopy

摘要: The ``hexagonal ferrites'' comprise a quasipolytypic series of ferrimagnetic oxides containing Ba, Fe3+, and divalent metal cation (Me2+). These encompass family hexagonal rhombohedral mixed‐layer structures derived by the c‐axis stacking two complex invariant building blocks, mainly ``M'' ``Y''. M element is 5‐anion‐layer block, 11.6 A in height with composition BaFe12O19, Y 6‐anion‐layer 14.5 high Ba2Me22+Fe12O22. largest series, M2Yn(n=0 to 21), involves blocks variable number blocks. Permutation elements allows polytypism within given stoichiometry, i.e., ratio. More than twenty (20) their polytypes have been examined electron microscopy after direct replication basal face.Basal faces which were etched dilute hydrochloric acid exhibit etch steps sub‐unit‐cell heights. specific s...