Phase transition and energy storage behavior of antiferroelectric PLZT thin films epitaxially deposited on SRO buffered STO single crystal substrates

(Pb_0.98, La_0.02)(Zr_0.95, Ti_0.05)O₃ (PLZT) thin films of 300 nm thickness were epitaxially deposited on (100), (110), and (111) SrTiO₃ single crystal substrates by pulsed laser deposition. X-ray diffraction line and reciprocal space mapping scans were used to determine the crystal structure. Tetragonal ((001) PLZT) and monoclinic M_A ((011) and (111) PLZT) structures were found, which influenced the stored energy density. Electric field-induced antiferroelectric to ferroelectric (AFE→FE) phase transitions were found to have a large reversible energy density of up to 30 J/cm³. With increasing temperature, an AFE to relaxor ferroelectric (AFE→RFE) transition was found. The RFE phase exhibited lower energy loss, and an improved energy storage efficiency. The results are discussed from the perspective of crystal structure, dielectric phase transitions, and energy storage characteristics. Besides, unipolar drive was also performed, providing notably higher energy storage efficiency values due to low energy losses.