Electrical resistance anomaly in Fe3Al-based alloys

The temperature dependence of electrical resistivity in (Fe1-xMx)3 Al with M = Ti, V, Cr, Mn and Mo shows anomalies characterized by: (i) a resistance maximum near the Curie temperature; (ii) a negative resistivity slope at higher temperatures up to 1000 K and above; and (iii) an inflection point as a signature of the D03-B2 phase transformation. A remarkable stabilization of the D03 phase is caused by the electron concentration effect due to the site preference of the substituting M atoms. In particular, the Heusler-type Fe2VAl compound exhibits a semiconductor-like behavior with the resistivity reaching 3000 μm cm at 2 K and is regarded as a possible candidate for a 3d heavy-fermion system.