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Title: Low temperature hopping in granular oxides La{sub 0.67}Ca{sub 0.33}MnO{sub 3} and La{sub 0.5}Sr{sub 0.5}CoO{sub 3}

We studied electrical transport in La{sub 0.67}Sr{sub 0.33}MnO{sub 3} (LCMO) and La{sub 0.5}Sr{sub 0.5}CoO{sub 3} (LSCO) nanocrystals over a temperature range of 0.4 K ≤ T ≤ 5 K. In both samples, two distinct behaviors of the conductivity are observed. For T>1 K, the variable range hopping regime is observed in LCMO sample with enhancement of the relative permittivity. In contrast, this behavior is not consistent with the extracted parameters in LSCO sample. For T<1 K, the transport is believed to occur through the metallic droplets connected to the intergranular regions where the negative magnetoresistance is due to spin-polarized tunneling phenomenon.
Authors:
; ;  [1] ;  [2] ; ;  [3]
  1. Research Group, Equipe de Semiconducteurs, de Nanotechnologie et de Programmation Scientifique, Physics department, Ibn Zohr University, Faculty of Sciences, B.P 8106, Hay Dakhla, 80000 Agadir (Morocco)
  2. School of Electronic and Electrical Engineering Sungkyunkwan University, Sunwon 440-746, Korea and Department of Physics, National Taiwan University, Taipei, Taiwan (China)
  3. Laboratoire Electronique, Électrotechnique, Automatique et Traitement de l'Information (EEA TI). Département Génie Electrique Université Hassan II Mohammedia Casablanca, Faculté des Sciences et Techniques de Mohamme (Morocco)
Publication Date:
OSTI Identifier:
22264044
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1574; Journal Issue: 1; Conference: International cryogenic materials conference, Anchorage, AK (United States), 17-21 Jun 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DROPLETS; MAGNETORESISTANCE; NANOSTRUCTURES; OXIDES; PERMITTIVITY; SPIN ORIENTATION; TUNNEL EFFECT