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Free keywords:
Chemical bonding, Germanium, Heat capacity, Magnetic susceptibility, Manganese, Charge transfer, Chemical analysis, Crystal structure, Electronic density of states, Germanium, Germanium compounds, Magnetic susceptibility, Magnetism, Manganese, Manganese compounds, Specific heat, Thermal conductivity, Thermoelectric equipment, Thermoelectricity, Band structure calculation, Chemical bondings, Ferromagnetic transitions, High-temperature synthesis, Low thermal conductivity, Metallic conductivity, Thermoelectric figure of merit, Thermoelectric properties, Chemical bonds
Abstract:
Mn3Ge5 was obtained by high-pressure, high temperature synthesis. The compound adopts a Nowotny-Chimney-Ladder type crystal structure [tetragonal, space group P4n2, a = 5.7449(1) Å, c = 13.9096(4) Å, Z = 4]. Magnetic measurements reveal a ferromagnetic transition around 40 K and metallic conductivity in the temperature range from 3 K to 350 K. Despite a low thermal conductivity, the metallic character of the sample and the low Seebeck coefficient result in low values for the thermoelectric Figure of merit, ZT. Band-structure calculations show that the Fermi level is located slightly below a pseudo-gap in the electronic density of states. Chemical bonding analysis in position space discloses moderate charge transfer and two- as well as three-atomic directed, heteroatomic bonding involving both the manganese and the germanium atoms. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.