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

Autor(es)

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

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS; v. 98, p. 38-42, NOV 2016.
• Citações Web of Science: 5

Resumo

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)

• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 14/01371-5 - Obtenção de memórias com LaNiO3 e LaNiO3/BaTiO3 utilizando PLD
• Beneficiário: Leonélio Cichetto Junior
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado