The Influence of Ni on the Transport Properties of CoSb₃

Abstract

The effect of Ni doping on the Co site of the binary skutterudite CoSb 3 is investigated. We measured resistivity, Hall effect, magnetoresistance, thermopower, thermal conductivity, and magnetization of a series of samples of the form Co 1-x Ni x Sb 3 with x in the range x=0 to x=0.01. We find that Ni takes the tetravalent state Ni 4+ , assumes the d 6 electronic configuration for the lower energy non-bonding orbitals, and gives an electron to the conduction band. Ni doping dramatically suppresses the thermal conductivity, changes the temperature dependence of the thermopower, and increases the carrier concentration. Low temperature anomalies in thermopower, Hall coefficient and magnetoresistance are found.

Influence of filler element and Ni-substitution on thermoelectric properties of multi-filled skutterudites

“…5 and 6). A similar situation was also observed for Co 1−x Ni x Sb 3 [19,21]. At higher Ni contents, |S| decreases due to an increase of the charge carrier concentration [20,25].…”

“…5d displays the temperature dependent Ä for Ca y Mm y (Co 1−x Ni x ) 4 Sb 12 . Unlike the apparent suppression in the thermal conductivity for Ni-substitution in unfilled CoSb 3 [20,21,25] and Ba 0.3 (Co 1−x Ni x ) 4 Sb 12 [22], the impact of Ni-doping on Ä especially on Ä l for Ca y Mm y (Co 1−x Ni x ) 4 Sb 12 is very weak. Similar results were reported by Puyet et al for Ca 0.18 (Co 1−x Ni x ) 4 Sb 12 [24,26].…”

“…In addition, it is well known that Ni-doping in CoSb 3 -based skutterudites not only controls the conduction type but also enhances ZT through reduction of both electrical resistivity and thermal conductivity [19][20][21][22][23][24][25][26]. Therefore, it is of interest to investigate the impact of Ni on multi-filled skutterudites.…”