Thermoelectric properties of single-phase full-Heusler alloy Fe2TiSi films with D03-type disordering

Fe 2TiSi has been expected to be one of the high-performance thermoelectric full-Heusler alloys. Here, we experimentally clarify the room-temperature Seebeck coefficient ( S) and thermal conductivity ( κ) for the Fe 2TiSi films. Using a molecular beam epitaxy technique, we demonstrate the high degree of L 2 1-ordering and the homogeneous single-phase structure in the Fe 2TiSi films. We find that the intrinsic conduction carriers of the Fe 2TiSi films are holes and impurity-induced carrier scattering is indicated, derived from weak magnetic moments due to the presence of D 0 3-type (Fe ⇔ Ti) structural disorder in the Fe 2TiSi film. From reliable measurements for thin films, the values of S and κ are estimated to be 101 μV/K and 5.6 W/(m K), respectively, at room temperature. This study will open a new way for full-Heusler alloy thermoelectric materials other than those in Fe 2VAl systems.