Thermoelectric power studies on Nd{sub 1.82{minus}{ital x}}Sr{sub {ital x}}Ce{sub 0.18}CuO{sub {ital y}}:{ital x}{le}0.18 superconductors

Journal Article · Fri Nov 01 04:00:00 EST 1996 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.363500· OSTI ID:385643

Singh, O G; Padalia, B D ^[1]; Prakash, O ^[2]; Agarwal, S K; Narlikar, A V ^[3]

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1. Department of Physics, Indian Institute of Technology, Powai, Bombay 400 076 (India)
2. Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Powai, Bombay 400 076 (India)
3. Superconductivity Group, National Physical Laboratory, New Delhi 110012 (India)

Thermoelectric power ({ital S}) studies on a Nd{sub 1.82{minus}{ital x}}Sr{sub {ital x}}Ce{sub 0.18}CuO{sub {ital y}}:{ital x}{le}0.18 superconducting system in the temperature range 35{endash}250 K are reported here. In the {ital x}=0.09 sample, synthesized in the reduced environment, the small magnitude of {ital S} is highly metalliclike and its sign is negative, a characteristic of electron conduction. The sign of {ital S} for the {ital x}=0.18 sample shows a crossover below 75 K from negative to positive, in apparent conflict with electronic conduction. Interestingly, after oxygenation this sample exhibits a broadened but positive phonon draglike peak. This oxygenated sample shows overcompensation of the carrier (electron) concentration. Critical analysis of the data suggests that Sr doping seemingly causes a competition between electron- and holelike conduction. The slope {ital dS}/{ital dT} is, in general, negative suggesting that the main contribution is coming from the diffusive part. The observed thermopower features seem to fall in line with the theoretical curves of Durczewski and Ausloos [Z. Phys. B {bold 85}, 59 (1991); Phys. Rev. B {bold 53}, 1762 (1996)] based on the inelastic scattering of quasifree electrons by phonons. {copyright} {ital 1996 American Institute of Physics.}

• OSTI ID: 385643
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 80; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERIUM OXIDES
COPPER OXIDES
DOPED MATERIALS
HIGH-TC SUPERCONDUCTORS
NEODYMIUM OXIDES
STRONTIUM OXIDES
THERMOELECTRIC PROPERTIES
TRANSITION TEMPERATURE