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Author Morozova, Natalia V. ♦ Shchennikov, Vladimir V. ♦ Ovsyannikov, Sergey V.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ BCC LATTICES ♦ CERIUM ALLOYS ♦ CHROMIUM ♦ ELECTRON TRANSFER ♦ EUROPIUM ♦ GOLD ♦ HCP LATTICES ♦ HYSTERESIS ♦ IRON-ALPHA ♦ LANTHANUM ♦ MANGANESE ♦ PHASE TRANSFORMATIONS ♦ SCANDIUM ♦ SEEBECK EFFECT ♦ STRESSES ♦ THERMOELECTRIC PROPERTIES ♦ THERMOELECTRICITY ♦ TIN ♦ YTTERBIUM ♦ YTTRIUM
Abstract We report results of systematic investigations of the thermoelectric properties of a number of rare-earth metals, transition metals, and other metals under high pressure up to 20 GPa at room temperature. We studied an effect of applied pressure on the Seebeck effect of scandium (Sc), yttrium (Y), lanthanum (La), europium (Eu), ytterbium (Yb), iron (Fe), manganese (Mn), chromium (Cr), gold (Au), tin (Sn), and CeNi alloy. We found that the high-pressure behavior of the thermopower of three rare-earth metals, namely, Sc, Y, and La, follows a general trend that has been established earlier in lanthanides, and addressed to a s → d electron transfer. Europium and ytterbium, on the contrary, showed a peculiar high-pressure behavior of the thermopower with peaks at near 0.7–1 GPa for Eu and 1.7–2.5 GPa for Yb. Chromium, manganese, and tin demonstrated a gradual and pronounced lowering of the absolute value of the thermopower with pressure. Above 9–11 GPa, the Seebeck coefficients of Mn and Sn were inverted, from n- to p-type for Mn and from p- to n-type for Sn. The Seebeck effect in iron was rather high as ∼16 μV/K and weakly varied with pressure up to ∼11 GPa. Above ∼11 GPa, it started to drop dramatically with pressure to highest pressure achieved 18 GPa. Upon decompression cycle the thermopower of iron returned to the original high values but demonstrated a wide hysteresis loop. We related this behavior in iron to the known bcc (α-Fe) → hcp (ε-Fe) phase transition, and proposed that the thermoelectricity of the α-Fe phase is mainly contributed by the spin Seebeck effect, likewise, the thermoelectricity of the ε-Fe phase—by the conventional diffusion thermopower. We compare the pressure dependencies of the thermopower for different groups of metals and figure out some general trends in the thermoelectricity of metals under applied stress.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-12-14
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 118
Issue Number 22


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