2 research outputs found
Properties of Pb(Zr,Ti)O ultrathin films under stress-free and open-circuit electrical boundary conditions
A first-principles-based scheme is developed to simulate properties of (001)
PbO-terminated Pb(ZrTi)O thin films that are under
stress-free and open-circuit boundary conditions. Their low-temperature
spontaneous polarization never vanishes down to the minimal thickness, and
continuously rotates between the in-plane and directions when
varying the Ti composition around x=0.50. Such rotation dramatically enhances
piezoelectricity and dielectricity. Furthermore, the order of some phase
transitions changes when going from bulk to thin films.Comment: 11 pages, 3 figure
Dependence of Curie temperature on the thickness of an ultrathin ferroelectric film
International audienceThe thickness dependency of the Curie temperature in stress-free Pb Zr0.5Ti0.5 O3 ultrathin films under open-circuit conditions is revealed from the computation of some nontrivial statistical quantities such as fourth-order cumulants , via a first-principles-based technique. For thicknesses above 16 Ã…, this dependency follows the usual finite-size scaling law with a critical exponent that is consistent with the one associated with the three-dimensional-random-Ising universality class. On the other hand, the Curie temperature-versus-film's thickness curve deviates from this scaling law below 12 Ã… while being rather well described by an empirical equation down to 8 Ã…