Polarization behaviors of (Bi 3.15 Nd 0.85) Ti 3 O 12 thin films deposited by radio-frequency magnetron sputtering

Abstract

Ferroelectric (Bi3.15 Nd0.85) Ti3 O12 (BNdT) thin films of random orientation have been successfully deposited on PtTi SiO2 Si (001) by radio-frequency magnetron sputtering, followed by rapid thermal annealing at 700 °C. They exhibit a remanent polarization 2 Pr of 23.2 μC cm2 and a coercive field EC of 112 kVcm at an applied voltage of 10 V. These BNdT films also show a switchable polarization (ΔP= Psw - Pns) of 12.9 μC cm2 at 5 V, together with an almost fatigue-free behavior up to 1.4× 1010 switching cycles at both 100 and 150 °C. They demonstrate desirable retention and imprint behaviors at 100 °C, while a further increase in temperature up to 150 °C led to an acceleration in both retention loss and imprint behavior, which can be accounted for by the thermally assisted redistribution of defects and space charges. Studies of the ac dependence of relative permittivity suggest the occurrence of domain-wall pinning, which is a commonly observed phenomenon in oxide ferroelectric thin films. © 2005 American Institute of Physics.