ELECTRICAL-RESISTANCE ANOMALY AND HALL-EFFECT IN (FE1-VX)(3)AL ALLOYS

We have measured the electrical resistivity and the Hall effect in D0( 3)-type (Fe1-xVx)(3)Al alloys with 0 less than or equal to x less than or equal to 0.38. When substituted by V, the electrical resistivity i ncreases rapidly at low temperatures and shows an anomalous temperatur e dependence: an occurrence of a resistance maximum at or near the Cur ie point Te and a negative resistivity slope above T-C. The tendency o f the negative temperature dependence increases markedly with the V co mposition, accompanying a sharp drop in T-C. In particular, the Heusle r-type Fe2VAl alloy (x = 0.33) exhibits a semiconductor-like behavior with an extremely large resistivity reaching 30 mu Omega m at 4.2 K. I n parallel with the increase in resistivity at low temperatures, the H all coefficient of the order of 10(-8) m(3)/C also increases rapidly w ith the V substitution, suggesting a reduction in the carrier concentr ation.