Remarkable increase of Curie temperature in doped GdFeSi compound

The GdFe1-xTixSi (x = 0–0.2) intermetallic compounds have been studied. They crystallize into the tetragonal CeFeSi (P4/nmm)–type structure. With increasing Ti content, the Curie temperature TC and the lattice parameter c increase quickly for x = 0–0.1 and then, more moderate because of the solubility limit, whereas the saturation magnetization at 4 K and the lattice parameter a remain almost unchanged. The theoretical DFT + U calculations showed that the growth of Ti content affects the electronic structure of GdFe1-xTixSi by significantly increasing the density of electron states at the Fermi level N(EF). At the same time, the total magnetic moment does not change because both Fe and Ti are non-magnetic in these intermetallic compounds. The growth of the density of electron states near the Fermi level is accompanied by the rapid growth of TC in the GdFe1-xTixSi system.