Effect of addition of B or C on thermoelectric properties of heavy fermion intermetallic compound YbAl3

The effect of addition of B or C on thermoelectric properties of YbAl3 was investigated. YbAl3 is well known as one of heavy fermion intermetallic compounds, which generally possess relatively large Seebeck coefficient and extremely low electrical resistivity. Yb1.05Al3Mx (M = B or C, x = 0–0.10) showed almost single phase with AuCu3-type structure. The Seebeck coefficient and electrical resistivity of Yb1.05Al3 were hardly affected by the addition of B or C, which showed that there was no difference in the carrier density among these compounds. The addition of C, or especially B, was effective for the reduction of the thermal conductivity, which was mainly attributed to the reduction of the lattice contribution. As a result, Yb1.05Al3B0.10 showed a maximum ZT of about 0.33 at 323 K, which was a little larger than ZT of Yb1.05Al3.

► The effect of addition of B or C on thermoelectric properties of YbAl3 was studied.
► The Seebeck coefficient was hardly affected by the addition of B or C.
► The electrical resistivity was hardly affected by the addition of B or C, either.
► The addition of B was effective for the reduction of the thermal conductivity.
► Yb1.05Al3B0.10 showed a maximum ZT of about 0.33 at 323 K.