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}

Journal Article · Mon Jan 27 00:00:00 EST 2014 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4860637· OSTI ID:22264044

Tata, O. ^[1]; Liang, C. -T. ^[2]; Idrissi, H. El; Zatni, A. ^[3]

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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)

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.

• OSTI ID: 22264044
• Journal Information: AIP Conference Proceedings, Vol. 1574, 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); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DROPLETS
MAGNETORESISTANCE
NANOSTRUCTURES
OXIDES
PERMITTIVITY
SPIN ORIENTATION
TUNNEL EFFECT