Structural and dielectric characterizations of relaxor/ferroelectric superlattice films Pb(Sc1/2Nb1/2)O3/PbTiO3 fabricated on a single-lattice scale

• Published in: Journal of applied physics Vol. 103; no. 9
• Main Authors: Asanuma, Shutaro, Uesu, Yoshiaki, Malibert, Charlotte, Kiat, Jean-Michel
• Format: Journal Article
• Language: English
• Published: 01.05.2008
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.2912993

Relaxor/ferroelectric superlattice (SL) films Pb(Sc1/2Nb1/2)O3(PSN)/PbTiO3(PT) with nine different PT concentrations x are fabricated by a pulsed laser deposition method, which keeps the total film thickness at 100 nm. The structure of the SL films is examined by out-of-plane and in-plane x-ray diffractions. All films are epitaxial and their SL structures are coherent over the whole sample. SL reflections up to the fourth order are observed. Lattice constants of the PT and PSN layers in the SL are determined, and the PT lattice constant exhibits a marked increase at xm=32%. At this PT concentration, this phenomenon is due to a polarization reorientation from the a-axis oriented to the c-axis oriented domain. The complex dielectric constants of all samples are measured in the frequency region from 1 to 106 Hz, and the intrinsic dielectric constant ε of the SL is derived by an analysis using the equivalent electric circuit model. ε takes the maximum at xm. The possible origin of this peculiar phenomenon is discussed.