Ferroelectric lithography investigations (Fig. )) confirm the trend that higher DC fields are required for vertical domain switching as the B-site Ti concentration decreases and the presence of the m = 6 phases increases. Applying a vertical DC bias of 50 V to specific regions on the thin film surface during the "write" step resulted in ferroelectric polarization reversal in both the Bi6Ti2.80Fe1.52Mn0.68O18 (56% Ti at B-site) and Bi6Ti2.50Fe1.77Mn0.73O18 (50% Ti at B-site) samples, as detected by the subsequent PFM scan during the "read" step ((Fig. (f), (g), (j), (k)). However, in the Bi6Ti230Fe1.95Mn0.75O18 (46% Ti at B-site) sample, a higher DC bias of 90 V was necessary for vertical domain switching (Fig. ).