Cation ordering schemes for $A$-site 2D (layered) ordering in $A A^{\prime} B B^{\prime} \mathrm{O}_{6}$ perovskites, $B$ and $B^{\prime}$ completely (a) disordered and (b) ordered arrangement.
Cation ordering schemes for A-site 2D (layered) ordering in A A^{\prime} B B^{\prime} \mathrm{O}_{6} perovskites, B and B^{\prime} completely (a) disordered and (b) ordered arrangement.