Electrical transport, thermal transport, and elastic properties of M₂AlC (M=Ti, Cr, Nb, and V)

In this paper we report on a systematic investigation, in the 5 to 300 K temperature regime, of the electronic, magnetotransport, thermoelectric, thermal, and elastic properties of four M₂AlC phases: Ti₂AlC, V₂AlC, Cr₂AlC, and Nb₂AlC. The electrical conductivity, Hall coefficient, and magnetoresistances are analyzed within a two-band framework assuming a temperature-independent charge carrier concentration. As with other MAX-phase materials, these ternaries are nearly compensated, viz. the densities and mobilities of electrons and holes are almost equal. There is little correlation between the Seebeck and Hall coefficients. With Young’s and shear moduli in the 270 GPa and 120 GPa range, respectively, the phases studied herein are reasonably stiff. With room temperature thermal conductivities in the 25 W∕m K range (45 W∕m K for V₂AlC) they are also good thermal conductors.