Manifestation of unusual size effects in granular thin films prepared by pulsed laser deposition

Author(s)

Sergeenkov, S. ; Cichetto, Jr., L. ; Diaz, J. C. C. A. ; Bastos, W. B. ; Longo, E. ; Araujo-Moreira, F. M.

• Document type: Journal article
• Source: JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS; v. 98, p. 38-42, NOV 2016.
• Web of Science Citations: 5

Abstract

We demonstrate manifestation of some rather unusual size effects in granular thin films prepared by a pulsed laser deposition technique. We observed that the temperature dependence of resistivity rho(T) notably depends on the relation between the grain size R-g and the film thickness d. Namely, more granular LaNiO3 thin films (with small values of R-g) grown on LaAlO3 substrate are found to follow a universal rho(T) proportional to T-3/2 law for all the measured temperatures. While less granular thin films (with larger values of R-g), exhibit a more complicated behavior accompanied by a clear-cut crossover (around T-cr = 200 K), from rho(T) proportional to T-3/2 (for 20 K < T < 200 K) to rho(T) proportional to T (for 200 K < T < 300 K). The obtained results are attributed to manifestation of the finite temperature size effects (when an average grain size R-g becomes comparable with the thermal de Broglie wavelength A) leading to the crossover temperature T-cr proportional to (diRg)(2). (C) 2016 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 14/01371-5 - Obtention of memories with LaNiO3 and LaNiO3/BaTiO3 using PLD
• Grantee: Leonélio Cichetto Junior
• Support type: Scholarships in Brazil - Post-Doctorate