Analyzed by Kelvin Force Microscopy of PbZr_(0.3)Ti_(0.7)O_3 thin films grown on La_(0.5)Sr_(0.5)CoO_3 or LaMnO_3 bottom electrodes

摘要

We have investigated structural and electrical properties of PbZr_(0.3)Ti_(0.7)O_3 (PZT) thin films deposited by pulsed laser deposition methods. In order to improve the ferroelectric properties of PZT thin films, we have controlled grain size or surface morphology by changing bottom electrode or deposition time. PZT thin films have been deposited on La_(0.5)Sr_(0.5)CoO_3 (LSCO) or LaMnO_3 (LMO) bottom electrodes with LaAlO_3 substrates during different deposition times. X-ray diffraction data have shown that all the PZT films and bottom electrodes are highly oriented with their c-axes normal to the substrates. The thickness of each film is determined by field-emission scanning electron microscope. We have also observed alternation of grain sizes (80～180 nm) by using atomic force microscopy mode and surface potential distribution and retention behavior of ferroelectric domains by using Kelvin force microscopy mode. A PZT/LMO structure has shown superior ferroelectric and retention properties to a PZT/LSCO structure.