Electronic structure and magnetism of ferromagnetic GdTiSi and GdTiGe

Crystal structure and temperature dependence of magnetic susceptibility and electrical resistivity have been determined for GdTiSi and GdTiGe. Both co mpounds order ferromagnetically and for GdTiGe T-C is 374 K which is a very high value for such kinds of compounds. The electronic structure for both compounds has been investigated by photoelectron spectroscopy and compared with calculations performed using the TB-LMTO method. A very good agreement with experiment was obtained, especially for GdTiGe. A strong hybrydizatio n between the d states from Gd and Ti was found and a significant polarizat ion of the Ti 3d electrons in GdTiGe was obtained which may be related to t he enhanced indirect exchange between Gd magnetic moments.