Physical properties of Heusler-like Fe2VAl - art. no. 165109

A comprehensive characterization of the compound Fe2VAl was carried out. Sa mples grown by are melting or the Bridgman method have Al and Fe deficienci es of up to 5 at. %. Czochralski-grown samples were Fe rich and Al deficien t. X-ray diffraction implies appreciable antisite disorder in all of our sa mples. Fourier-transform infrared (FTIR) spectroscopy measurements showed t hat the carrier density and scattering time had little sample-to-sample var iation or temperature dependence for near-stoichiometric samples. FTIR and de resistivity suggest that the transport properties of Fe2VAl are influenc ed by both localized and delocalized carriers, with the former primarily re sponsible for the negative temperature coefficient of resistivity. Magnetiz ation measurements reveal that near-stoichiometric samples have superparama gnetic clusters with at least two sizes of moments. We conclude that in Fe2 VAl, antisite disorder causes significant modification to the semimetallic band structure proposed theoretically. With antisite disorder considered, w e are now able to explain most of the physical properties of Fe2VAl. None o f our data suggest heavy-fermion behavior in our samples.