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Enhancement in thermoelectric power of Ce(Ni 1− x Cu x ) 2 Al 3 : An implication of two‐band conduction
Author(s) -
Yadam Sankararao,
Singh Durgesh,
Venkateshwarlu D.,
Gangrade Mohan Kumar,
Samatham S. Shanmukharao,
Ganesan V.
Publication year - 2015
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201451317
Subject(s) - seebeck coefficient , condensed matter physics , electrical resistivity and conductivity , magnetoresistance , thermoelectric effect , materials science , crystallite , fermi level , thermal conduction , band gap , kondo effect , electron , magnetic field , physics , thermodynamics , metallurgy , quantum mechanics , composite material
The thermoelectric power (TEP), resistivity, and heat capacity of the polycrystalline Ce(Ni 1− x Cu x ) 2 Al 3 system, for x = 0.0–0.4, are reported. A clear enhancement of TEP at low temperatures is seen upon substitution of Cu and is expected to be useful for low‐temperature thermoelectric applications. To understand such an enhanced TEP we have employed a two‐band model based on the Ce‐4f and conduction bands proposed by Gottwick et al. A clear evolution of a 4f band moving toward the Fermi level that is becoming sharpened is seen and is predicted to be close to resonance. The fit parameters of the TEP ( S ) are physically reasonable. The resistivity data shows an evolution from a simple compensated metal to a paramagnetic one via the Kondo route. This is in line with TEP parameters. In addition, a clear enhancement seen in the electronic part of the heat capacity upon Cu substitution and the evolution of magnetoresistance behavior corroborates the results. Possible bipolar effects are also taken into consideration along with an electron–phonon interaction term to explain the almost temperature‐independent part of the resistivity, still yielding a considerable component of disorder.