LAUSR

Abstract Centimeter-sized bulk CaMgSi intermetallic compounds are synthesized and its thermoelectric properties are reported in this study. The CaMgSi intermetallic compound consists of nontoxic, inexpensive and lightweight elements, and has a pseudogap near the Fermi energy, E F , in the electronic density of states. The bulk Ca 33.3+ x Mg 33.3− x Si 33.3 ( x  = −12–3) samples were synthesized by mechanical ball milling (MM) of the CaH 2 , Mg and Si powders, and subsequent pulse current sintering (PCS). It was found that both the MM and PCS processes are essential in order to synthesize a bulk CaMgSi sample. Off-stoichiometric bulk CaMgSi samples were also synthesized. Thermoelectric measurements revealed that the bulk CaMgSi samples have p-type conductivity (Seebeck coefficient α  > 0), and also suggested that their temperature dependences of electrical resistivity, ρ , changed from metallic to semiconductor-like behavior with decreasing Ca content. As a result, the maximum value of the power factor, P , in the bulk Ca 33.3 Mg 33.3 Si 33.3 sample showed 0.42 mW m −1  K −2 at 433 K.