Structure and Thermoelectric Properties of β-FeSi2 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 Fe 0.98 Co 0.015 Si 2 as an example, it is shown that during the 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 the sample. In the region of low cobalt concentrations, upon transition to pure β-FeSi 2 , the sign and magnitude of thermopower change sharply.