Deterministic Dual Control of Phase Competition in Strained BiFeO_(3):A Multiparametric Structural Lithography Approach

The realization of a mixed-phase microstructure in strained BiFeO_(3)(BFO)thin films has led to numerous novel effects derived from the coexistence of the tetragonal-like monoclinic phase(T phase)and rhombohedral-like monoclinic phase(R phase).Strong strain and polarization diiferences between the phases should result in a high level of transformation plasticity,which enables the continuous alteration of the relative proportion of R and T states in response to external forces.Although the potential for utilizing such plasticity to control mixed-phase populations under external stimuli is evident,direct experi・mental evidence backed by equilibrium predictions has not yet been fully demonstrated.Here we demonstrate deterministic control of mixed-phase populations in an epitaxially strained BFO thin film through the application of localized stresses and electric fields in a reversible manne匚The results illustrate and rationalize deterministic control of mixed phases in strained BFO films,which could be crucial in tuning their functional properties.The findings also highlight a new multiparametric technique in the scanning probe lithography toolbox based on tip-assisted electric and strain field manipulation of functional properties that might find application beyond the ferroelectric domain and structural phase lithography.