TY - JOUR AU - Pertsev, N. A. AU - Rodriguez Contreras, J. AU - Kukhar, A. I. AU - Hermanns, B. AU - Kohlstedt, H. AU - Waser, R. TI - Coercive field of ultrathin PbZr0.52Ti0.48O3 epitaxial films JO - Applied physics letters VL - 83 SN - 0003-6951 CY - Melville, NY PB - American Institute of Physics M1 - PreJuSER-32036 SP - 3356 PY - 2003 N1 - Record converted from VDB: 12.11.2012 AB - The polarization reversal in single-crystalline ferroelectric films has been investigated experimentally and theoretically. The hysteresis loops were measured for Pb(Zr0.52Ti0.48)O-3 films with thicknesses ranging from 8 to 250 nm. These films were grown epitaxially on SrRuO3 bottom electrodes deposited on SrTiO3 substrates. The measurements using Pt top electrodes showed that the coercive field E-c increases drastically as the film becomes thinner, reaching values as high as E(c)approximate to1200 kV/cm. To understand this observation, we calculated the thermodynamic coercive field E-th of a ferroelectric film as a function of the misfit strain S-m in an epitaxial system and showed that E-th strongly depends on S-m. However, the coercive field of ultrathin films, when measured at high frequencies, exceeds the calculated thermodynamic limit. Since this is impossible for an intrinsic coercive field E-c, we conclude that measurements give an apparent E-c rather than the intrinsic one. An enormous increase of apparent coercive field in ultrathin films may be explained by the presence of a conductive nonferroelectric interface layer. (C) 2003 American Institute of Physics. KW - J (WoSType) LB - PUB:(DE-HGF)16 UR - <Go to ISI:>//WOS:000185954400042 DO - DOI:10.1063/1.1621731 UR - https://juser.fz-juelich.de/record/32036 ER -