Ferroelectric Domain Imaging using PFM Piezoresponse Force Microscope

Ferroelectric Domain Imaging using PFM (Piezoresponse Force Microscope) X. Xiao, X. J. Yang, Y. Lu, W. Wang, Y. Z. Wu Schematic of PFM Piezoresponse Force Microscope has proved to be an effective tool to imaging the domain structures of ferroelectric materials and has been applied to probe localized polarization switching. By using PFM, Piezoelectric coefficient can be gotten by applying a drive DC offset at the sample changing from positive to negative. Besides, we can write a signal on the ferroelectric materials by applying a voltage higher than the switching critical point. This manipulation is regarded to be a fundamental means for further investigation of ferroelectric storage device. A lot of improvement is still in Apply an alternating voltage to sample/conductive tip need to get better results. E Piezoelectric Effect Øpolarization parallel to the field Domains extend Øpolarization opposite to the field Domains contraction Mechanically vibration of piezoelectric sample Induced oscillation of cantilever Measured by four-quadrant photodiode detector Signal Writing with PFM Polarize Domain u. Apply an DC voltage of 6 V to polarize the sample at an 3× 3μm 2 area u. Apply an DC voltage of -6 V to polarize the sample at an 1× 1μm 2 area u. Scan the sample with an alternative voltage at an area of 5× 5μm 2 V. Garcia et. al. , Nature 460, 81 -84 , 2009 Experiment Cantilever & Tip Electron Electrode Schematic for sample preparation piezoelectric loop PMN-PT LSMO Piezoelectric coefficient Morphology of the sample