Semiconductorlike Behavior of Electrical Resistivity in Heusler-typeFe2VAlCompound

An anomalous negative temperature dependence of electrical resistivity has been observed in $({\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{V}}_{x}{)}_{3}\mathrm{Al}$ alloys with V compositions up to $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.35$. In particular, the Heusler-type ${\mathrm{Fe}}_{2}\mathrm{VAl}$ compound is found to be on the verge of magnetic ordering and to exhibit a semiconductorlike behavior with the resistivity reaching $3000\ensuremath{\mu}\ensuremath{\Omega}\mathrm{cm}$ at 2 K, in spite of the possession of a clear Fermi cutoff as revealed in photoemission valence-band spectra. A substantial mass enhancement deduced from specific heat measurements suggests that ${\mathrm{Fe}}_{2}\mathrm{VAl}$ is a possible candidate for a $3d$ heavy-fermion system.