Lattice thermal conductivity of compounds with inhomogeneous intermediate rare-earth ion valence |
| |
Authors: | A V Golubkov L S Parfen’eva I A Smirnov H Misiorek J Mucha A Jezowski |
| |
Institution: | (1) Ioffe Physicotechnical Institute, Russian Academy of Sciences, ul. Politekhnicheskaya 26, St. Petersburg, 194021, Russia;(2) Institute of Low-Temperature and Structural Research, Polish Academy of Sciences, Wroclaw, 50-950, Poland |
| |
Abstract: | The thermal conductivity κ (within the range 4–300 K) and electrical conductivity σ (from 80 to 300 K) of polycrystalline Sm3S4 with the lattice parameter a=8.505 Å (with a slight off-stoichiometry toward Sm2S3) are measured. For T>95 K, charge transfer is shown to occur, as in stoichiometric Sm3S4 samples, by the hopping mechanism (σ ~ exp(?ΔE/kT) with ΔE ~ 0.13 eV). At low temperatures up to the maximum in the lattice thermal conductivity κph(T)], κph ~ T 2.6; in the range 20–50 K, κph ~ T ?1.2; and for T>95 K, where the hopping charge-transfer mechanism sets in, κph ~ T ?0.3 and a noticeable residual thermal resistivity is observed. It is concluded that in compounds with inhomogeneous intermediate rare-earthion valence, to which Sm3S4 belongs, electron hopping from Sm2+ (ion with a larger radius) to Sm3+ (ion with a smaller radius) and back generates local stresses in the crystal lattice which bring about a change in the thermal conductivity scaling of κph from T ?1.2 to T ?0.3 and the formation of an appreciable residual thermal resistivity. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|