Evolution of thermoelectric properties in EuxYb1−xB6 family

Autor: A. V. Bogach, N. A. Samarin, N. Yu. Shitsevalova, Mikhail A. Anisimov, A. V. Levchenko, V S Zhurkin, V. V. Glushkov, Vladimir V. Voronov, S. V. Demishev, V. B. Filipov
Rok vydání: 2020
Předmět:
Zdroj: Journal of Physics: Condensed Matter. 32:465601
ISSN: 1361-648X
0953-8984
DOI: 10.1088/1361-648x/aba864
Popis: Seebeck effect in the crystalline samples of EuxYb1-xB6 (x = 0, 0.082, 0.127, 0.9, 1) was investigated at temperatures 2-300 K. For all the compounds thermopower is shown to be well described by the sum of diffusion (S d = AT) and phonon drag components. The latter contribution is induced by quasilocal (Einstein) modes of ytterbium and europium ions with characteristic temperatures ΘE(YbB6) ≈ 91 K and ΘE(EuB6) ≈ 122 K. The estimation of effective mass m * of the charge carriers proves that increasing of Eu content induces crossover from 'heavy' holes with m h*(x ⩽ 0.127) ≈ 0.3-0.36 m 0 to 'light' electrons with m e*(x ⩾ 0.9) ≈ 0.12-0.13 m 0 (m 0-free electron mass). For the Eu-rich compounds we propose the existence of additional point on the phase diagram, which corresponds to short-range magnetic order with enhanced spin fluctuations preceding the stabilization of magnetic polarons.
Databáze: OpenAIRE