| Autor: |
BURKOV, A.T., NAKAMA, T., HEDO, M., SHINTANI, K., YAGASAKI, K., MATSUMOTO, N., NAGATA, Shoichi |
| Jazyk: |
angličtina |
| Rok vydání: |
2000 |
| Předmět: |
|
| Zdroj: |
Physical review. Third series. B, Condensed matter and materials physics. 61(15):10049-10056 |
| ISSN: |
1098-0121 |
| Popis: |
Resistivity (ρ) and thermopower (S) of spinel-type compounds CuIr2S4 and CuIr2Se4 have been measured at temperatures from 2 to 900 K under magnetic field from 0 to 15 T. The thermopower is positive in the metallic phase of both compounds at high temperatures, as well as in the low-temperature insulating state of CuIr2S4. The positive thermopower of the insulating phase implies p-type charge carriers, in agreement with the recent photoemission results. The low-temperature resistivity of CuIr2S4 is in good agreement with the Efros-Shklovskii variable-range hopping conductivity mechanism: ρ=ρ0exp[(T*/T)1/2]. The most striking result is that the resistivity of the metallic phases is well described by an exponential-type temperature dependence in a wide temperature range from 2 K to at least 900 K. This unusual result for metals type of the resistivity temperature dependence, as well as other features in the transport properties, imply a nonconventional conductivity mechanism. The magnetoresistivity Δρ is positive and proportional to H2, while magnetothermopower ΔS=S(H,T)-S(0,T) is very small for both compounds at all temperatures |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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