Relation between domain structure and pyroelectric response in as-grown epitaxial Pb(Zr0.2Ti0.8)O3 thin films on substrates with different resistivity. (September 2017)

• Record Type: Journal Article
• Authors: Pintilie, I.; Trinca, L.; Trupina, L.; Pasuk, I.; Pintilie, L.
• Is Part Of: Materials research bulletin. Volume 93(2017)
• Page Start: 201
• Page End: 207
• Publication Date: 2017-09
• Subjects: Pyroelectric -- Epitaxial -- Lead zirconate-titanate -- Thin film -- Domains; Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2017.04.054
• Languages: English
• ISSNs: 0025-5408

Abstract

Graphical abstract: Highlights: Epitaxial PZT thin films were deposited on crystalline substrates with different resistivity. The pyroelectric response was found to be lower for the film deposited on higher resistivity substrate. The lower pyroelectric response was attributed to different configurations of ferroelectric domains. The poling procedure applied for the film with low pyroelectric response was not effective, the film returning to a random domain configuration. Abstract: Epitaxial Pb(Zr0.2 Ti0.8 )O3 (PZT) thin films were grown by pulsed laser deposition on two slightly different types of single crystal substrates, namely SrTiO3 (STO) buffered with a thin layer of conductive SrRuO3 (SRO), and SrTiO3 doped with 0.5% Nb (STON). Although self-poling effect was expected in both cases, due to the compressive strain imposed by the substrate, it was found that the pyroelectric response of as-grown samples is with about two orders of magnitude larger for the PZT film deposited on SRO/STO compared to the one deposited on STON substrate. In order to explain the finding, the electrical properties were investigated and it was found that the quantities involved in the equation giving the magnitude of the pyroelectric signal, namely dielectric constant and electrical resistivity, have about the same values Therefore, the different pyroelectric response in the as-grown samples was explained by different structure of ferroelectric domains induced by the different carrier concentration in the two substrates: 90° domains for PZT on SRO/STO and 180° domains for PZT on STON. It appears that the resistivity of the substrate and its ability to compensate the depolarization field affect the domain structure, with impact on the pyroelectric response, although the strain conditions are similar in both cases. The trying to increase the pyroelectric response for the PZT film deposited on STON substrate by applying a poling process was not successful, as the 180° domain structure restores shortly after removing the poling field.