Electronic structure, magnetic properties and electrical resistivity of the Fe2V1-xTixAl Heusler alloys:: experiment and calculation

The aim of this work is to investigate electronic structure, magnetic properties and electrical resistivity of Fe2V1-x TixAl Heusler alloys. Numerical calculations give a pseudogap at the Fermi level for the majority-spin band of Fe2TiAl and a magnetic moment larger than 0.9 mu(B), whereas the ground state of Fe2VAl is calculated as a nonmagnetic semimetal with a very low total density of states at the Fermi level. In our calculations the remaining alloys of the Fe2V1-x TixAl series are nonmagnetic for x < 0.1 and weakly magnetic for 0.1 < x <= 1. The magnetic moment mu of the series of Fe2V1-xTixAl compounds scales with the number of valence electrons and fits well to the Slater-Pauling curve. We also present a study of the electronic transport properties and magnetic susceptibility. The resistivities p(T) of Fe2VAl and Fe2V0.9Ti0.1Al are large and exhibit a negative temperature coefficient dp/dT of the resistivity between 2 and 300 K. Below 20 K, (T) also shows an activated character. The magnetic susceptibility of Fe2VAl and Fe2V0.9Ti0.1Al shows a maximum at similar to 2 K which could reflect either the disorder effect or the hybridization gap, characteristic of Kondo insulators.