Thermoelectric properties of semiconductorlike intermetallic compounds TMGa3 (TM=Fe, Ru, and Os)

Amagai, Yasutaka; Yamamoto, Atsushi; Iida, Tsutomu; Takanashi, Y.

doi:10.1063/1.1803947

Cited by 66 publications

(82 citation statements)

References 26 publications

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“…Indeed, Ga 3 Ru exhibits relatively higher electrical resistivity ($10 2 mcm), 18) which is one-order higher than that of the Ga 2 Ru. We cannot discuss the latter trend at this stage because the bulk density or microprobe composition of hot-pressed Ga 2 Ru is not described in the Ref.…”

Section: Thermoelectric Propertiesmentioning

confidence: 99%

“…The maximum S value of the Al 2 Ru and Ga 2 Ru are $200 and $360 mV/K, respectively. As S of Ga 3 Ru below 500 K exhibits negative value, 18) therefore, it is reasonable to state that the difference in S between arc-melted and sintered Ga 2 Ru samples is caused by the secondary phase of Ga 3 Ru. On the other hand, comparative large difference in S between the arc-melted and sintered Al 2 Ru samples will be caused by a metallic secondary phase of AlRu.…”

Section: Thermoelectric Propertiesmentioning

confidence: 99%

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Thermoelectric Properties of Binary Semiconducting Intermetallic Compounds Al2Ru and Ga2Ru Synthesized by Spark Plasma Sintering Process

et al. 2010

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The authors report the electrical and thermal transport properties of binary semiconducting intermetallic Al 2 Ru and Ga 2 Ru compounds from 373 to 973 K. We synthesized sintered pellets of Al 2 Ru and Ga 2 Ru by the spark plasma sintering (SPS) method, resulted in a removal of small amount of a secondary phase and of cracks. The maximum Seebeck coefficient of Al 2 Ru and Ga 2 Ru shows a large positive value of 200 mV/K and 360 mV/K, respectively. In particular, a large power factor $2:8 mW/m-K 2 was obtained at 773 K in Ga 2 Ru compound. The dimensionless figures of merit ZT of sintered Al 2 Ru and Ga 2 Ru samples monotonically increase with increasing temperature and reach a maximum value of 0.20 and 0.45 at about 873 K and 773 K, respectively.

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Section: Thermoelectric Propertiesmentioning

confidence: 99%

Section: Thermoelectric Propertiesmentioning

confidence: 99%

Thermoelectric Properties of Binary Semiconducting Intermetallic Compounds Al2Ru and Ga2Ru Synthesized by Spark Plasma Sintering Process

et al. 2010

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“…Early reports on FeGa 3 classify the compound as a diamagnetic semiconductor with a narrow gap of 0.4-0.5 eV [31,32,[39][40][41][42]. The magnetic susceptibility increases strongly at temperatures above ∼500 K [39], suggestive of an approaching crossover to a paramagnetic metallic state.…”

Section: Introductionmentioning

confidence: 99%

Electronic correlations inFeGa3and the effect of hole doping on its magnetic properties

et al. 2014

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We investigate signatures of electronic correlations in the narrow-gap semiconductor FeGa 3 by means of electrical resistivity and thermodynamic measurements performed on single crystals of FeGa 3 , Fe 1−x Mn x Ga 3 , and FeGa 3−y Zn y , complemented by a study of the 4d analog material RuGa 3 . We find that the inclusion of sizable amounts of Mn and Zn dopants into FeGa 3 does not induce an insulator-to-metal transition. Our study indicates that both substitution of Zn onto the Ga site and replacement of Fe by Mn introduces states into the semiconducting gap that remain localized even at highest doping levels. Most importantly, using neutron powder diffraction measurements, we establish that FeGa 3 orders magnetically above room temperature in a complex structure, which is almost unaffected by the doping with Mn and Zn. Using realistic many-body calculations within the framework of dynamical mean field theory (DMFT), we argue that while the iron atoms in FeGa 3 are dominantly in an S = 1 state, there are strong charge and spin fluctuations on short-time scales, which are independent of temperature. Further, the low magnitude of local contributions to the spin susceptibility advocates an itinerant mechanism for the spin response in FeGa 3 . Our joint experimental and theoretical investigations classify FeGa 3 as a correlated band insulator with only small dynamical correlation effects, in which nonlocal exchange interactions are responsible for the spin gap of 0.4 eV and the antiferromagnetic order. We show that hole doping of FeGa 3 leads, within DMFT, to a notable strengthening of many-body renormalizations.

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“…A recent example is the electron doping of the intermetallic FeGa 3 that leads to enhanced thermoelectric figures of merit [2][3][4][5][6][7][8][9][10] and to emergent magnetic behavior accompanied by the possible observation of a Ferromagnetic Quantum Critical Point (FMQCP) [11][12][13][14][15][16][17][18][19][20][21] .…”

Section: Introductionmentioning

confidence: 99%

Magnetic order of intermetallicFeGa3−yGeystudied byμSRand<

et al. 2017

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Temperature dependent magnetization, muon spin rotation and 57 Fe Mössbauer spectroscopy experiments performed on crystals of intermetallic 0.14, 0.17, 0.22, 0.27, 0.29, 0.32) are reported. Whereas at y = 0.11 even a sensitive magnetic microprobe such as µSR does not detect magnetism, all other samples display weak ferromagnetism with a magnetic moment of up to 0.22 µB per Fe atom. As a function of doping and of temperature a crossover from short range to long range magnetic order is observed, characterized by a broadly distributed spontaneous internal field. However, the y = 0.14 and y = 0.17 remain in the short range ordered state down to the lowest investigated temperature. The transition from short range to long range order appears to be accompanied by a change of the character of the spin fluctuations, which exhibit spin wave excitations signature in the LRO part of the phase diagram. Mössbauer spectroscopy for y = 0.27 and 0.32 indicates that the internal field lies in the plane perpendicular to the crystallographic c axis. The field distribution and its evolution with doping suggest that the details of the Fe magnetic moment formation and the consequent magnetic state are determined not only by the dopant concentration but also by the way the replacement of the Ga atoms surrounding the Fe is accomplished.

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Thermoelectric properties of semiconductorlike intermetallic compounds TMGa3 (TM=Fe, Ru, and Os)

Cited by 66 publications

References 26 publications

Thermoelectric Properties of Binary Semiconducting Intermetallic Compounds Al<SUB>2</SUB>Ru and Ga<SUB>2</SUB>Ru Synthesized by Spark Plasma Sintering Process

Thermoelectric Properties of Binary Semiconducting Intermetallic Compounds Al<SUB>2</SUB>Ru and Ga<SUB>2</SUB>Ru Synthesized by Spark Plasma Sintering Process

Electronic correlations inFeGa3and the effect of hole doping on its magnetic properties

Magnetic order of intermetallicFeGa3−yGeystudied byμSRand<

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