Structure and thermoelectric properties of β-FeSi<sub>2</sub> doped with cobalt

The possibility of replacing iron with cobalt in iron disilicide is studied. It has been shown, that in a wide range of compositions, an attempt to replace iron with cobalt leads to the formation of cobalt silicides. Using the composition Fe0.98Co0.015Si2 as an example, it is shown that during directional crystallization and subsequent annealing of samples, a regular microstructure is formed. Anisotropy of thermoelectric properties is observed along and across the crystallization axis of sample. In the region of low cobalt concentrations, upon transition to pure β-FeSi2, the sing and magnitude of the thermopower change sharply.