Suchergebnisse

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; Government of the Russian Federation ; Project CICECO-Aveiro Institute of Materials - national funds through the FCT/MEC ; FEDER under the PT2020 Partnership Agreement ; CNPq: 304604/2015-1 ; CNPq: 400677/2014-8 ; Government of the Russian Federation: 16-02-00821-a ; Government of the Russian Federation: 02. A03.21.0006 ; Project CICECO-Aveiro Institute of Materials - national funds through the FCT/MEC: FCT UID/CTM/50011/2013 ; CNPq: 232241/2014-7 ; Thickness dependence of imprint and polarization dynamics of Pb1-xLax(Zr1-yTiy)(1-x/4)O-3 (PLZT) thin films is reported in this work. Asymmetries in the histograms of the local piezoresponse reveal an imprint effect in the studied films whose origin could be associated to Schottky barriers near the film-substrate interface. Time-resolved spectroscopic measurements shows that the local polarization relaxation follows the exponential dependence . A maximum relaxation time approximate to 2.18s was observed for the 350nm thick film. A similar thickness dependence between grain size, correlation length () and relaxation time () suggest an intrinsic relationship between them.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; Russian Foundation for Basic Research ; Government of the Russian Federation ; FCT/MEC ; FEDER ; CNPq: 304604/2015-1 ; CNPq: 400677/2014-8 ; CNPq: 232241/2014-7 ; Russian Foundation for Basic Research: 16-02-00821-a ; Government of the Russian Federation: 02.A03.21.0006 ; FCT/MEC: FCT UID/CTM/50011/2013 ; La-modified lead zirconate titanate (PLZT) thin films were prepared to study their physical properties at macro- and nanoscale. Piezoresponse force microscopy (PFM) studies suggest a local imprint behavior at room temperature. Confirmed by P-E hysteresis loops recorded at 180-300K, the imprint effect at room temperature tends to disappear at lower temperatures. In addition, the remanent polarization gradually increases and then decreases after reaching a maximum at around 243K. This behavior suggests the occurrence of a reentrant dipole glass or an activated electric field effect in the studied PLZT films.