Thermoelectric and magnetic properties of (Fe,Co)2TiSn Heusler compounds

Abstract

The substitution of Co for Fe in the Fe2TiSn Heusler compound resulted in a change in the magnetic properties. Although the Fe2TiSn and Fe2-xCoTiSn (x = 0.5–1.0) Heusler compounds were paramagnetic, the Fe2-xCoTiSn (x = 1.5–2.0) Heusler compounds were found to be ferromagnetic. The Fe2TiSn Heusler compound is a p-type thermoelectric material that has a positive Seebeck coefficient of 30 μV/K at room temperature. On the other hand, Co-substituted (Fe,Co)2TiSn Heusler compounds prepared in the present study were shown to be n-type thermoelectric materials, regardless of the Co content. The (Fe,Co)2TiSn Heusler compounds exhibited relatively low electrical resistivity values, ranging from 1.71 μΩm for the Co2TiSn compound to 11.5 μΩm for the Fe1.5Co0.5TiSn compound. It was found that the power factor of the Co2TiSn Heusler compound (647 μW/mK2 at room temperature) was more than double that of the Fe2TiSn Heusler compound.