Transport properties of Ce{sub 2}Ni{sub 2}Sn and Ce{sub 2}Pd{sub 2.05}Sn{sub 0.95} Kondo lattice systems

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.365113· OSTI ID:496442

Pinto, R P; Amado, M M; Braga, M E; de Azevedo, M M; Sousa, J B ^[1]; Chevalier, B; Etourneau, J ^[2]

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1. IFIMUP, University of Porto, 4150 Porto (Portugal)
2. Inst. Chemie Mat. Condensee Bordeaux (ICMCB-CNRS), Av. Schweitzer, 33608 Pessac Cedex (France)

We report experimental data on thermoelectric power S, electrical resistivity {rho}, and the magnetoresistivity of the antiferromagnet Kondo stannides Ce{sub 2}Ni{sub 2}Sn (T{sub N}=4.7 K) and Ce{sub 2}Pd{sub 2.05}Sn{sub 0.95} (T{sub N}=4.7 K). The essential features of the S(T) curves resemble those of heavy fermion systems such as CeCu{sub 2}Si{sub 2}: a broad and positive maximum at intermediate temperatures, followed by a sharper negative minimum at lower temperatures. S values are is considerably smaller in Ce{sub 2}Pd{sub 2.05}Sn{sub 0.95} than in Ce{sub 2}Ni{sub 2}Sn. The positive peak originates from the incoherent Kondo scattering by the excited crystal field levels of the Ce ion ground state. The negative peak might be related to the shape of the density of states associated with the Abrikosov{endash}Suhl resonance. The change of sign in S(T) between its minimum and maximum at T{sup {asterisk}} can be assigned to the fact that the Fermi level sinks below the upper band at T{gt}T{sup {asterisk}}. This behavior and the maximum observed in the {rho}(T) curve at this temperature can be discussed in terms of the electron polaron model, although one must also take into account the crystal field effect. The role played by the crystal field effect, which is more important in Ce{sub 2}Pd{sub 2.05}Sn{sub 0.95}, is analyzed for this compound, providing the magnitude of the crystal field splitting. Magnetoresistivity was also measured in both compounds. The results are consistent with the important role of the Kondo effect at low temperatures and suggest the splitting of the double degenerate bands at T{gt}T{sup {asterisk}}. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 496442
• Report Number(s): CONF-961141--
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 81; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIFERROMAGNETIC MATERIALS
CERIUM ALLOYS
CRYSTAL FIELD
ELECTRIC CONDUCTIVITY
FERMI LEVEL
KONDO EFFECT
MAGNETORESISTANCE
NICKEL ALLOYS
PALLADIUM ALLOYS
POLARONS
TEMPERATURE DEPENDENCE
THERMOELECTRIC PROPERTIES
TIN ALLOYS