clearly demonstrate a shift from a pure m = 5 phase (in Bi6Ti2.7Fe1.62Mn0.68O18 (see The XRD pattern for Bi6Ti2.3Fe2.0Mn0.7O18, with the lowest Ti content of the samples investigated, predominantly exhibits m = 6 characteristics, closely matching a simulated pattern for a refined reference model, as discussed in Supplementary Information Section SI3.2 and shown in Figure . A summary of the results from the two-phase XRD modeling results is provided in Table , showing a clear trend toward the structural evolution of higher-layered Aurivillius phases to accommodate increased magnetic cation substitution.