Structural data was collected using x-ray diffractometer. The XRD data include 2theta-omega and 2theta measurement at chi 71 and phi 45. They are all converted to .csv files. PFM data is included in the data set in .001 and .dat format. .001 shows piezo-response force microscopy (PFM) poled images that one can access via NanoscopeAnalysis software to view square poled images indicating bi-stable ferroelectric states, and .dat file shows piezo-response force spectroscopy (PFS) measurement which shows phase and amplitude hysteresis loops indicating phase change in localised area. Hard x-ray photoelectron spectroscopy was collected from both synchrontron facility (Diamond, Oxford, UK) and lab based XPS (Manchester, UK). All the data is available in .vms format which can be accessed via CasaXPS software. Ferroelectric characterization was done via piezo-response force microscopy and ferroelectric tester (AixACCT TF Analyzer 2000). Theoretical calculations were done using DFT calculations. DFT calculations shows projected density of states (PDOS) for LSMO, which is used as bottom electrode in this work. Theoretical calculations show different results than experimental results indicating changes observed in experiment (increase in valence band) is not driven by redox reaction.

All the figures are available in 'Figures' folder either in .fig format or .svg format (accessible via Inkscape software).