SOME TRANSPORT-PROPERTIES OF SINGLE-CRYSTALS OF GROUP-VA TRANSITION-METAL DISILICIDES

Although transition metal disilicides are used in the form of thin films, single crystals are needed to study their intrinic properties. Single crystals of Group Va transition metal disilicides, namely VSi2, NbSi2 and TaSi2, have been successfully grown by Czochralski pulling from a levitated melt. The good quality of our crystals is shown by the high residual resistance ratios (VSi2:RRR > 20; NbSi2:RRR > 220; TaSi2:RRR > 400). The three compounds crystallize in the same hexagonal structure (C40, space group P6(2)22). Crystallographic and temperature dependences of the resistivity and of the magnetoresistance (H perpendicular-to less-than-or-equal-to 7.4 T) have been measured from 4.2 K up to room temperature. All the three materials show a metallic behaviour and some anisotropy, which is of the order of 2 for the three compounds. The magnetoresistance measurements show that VSi2 and TaSi2 are compensated metals with relatively small charge carrier concentrations (VSi2:n almost-equal-to 0.15 electrons/formula unit; TaSi2:n almost-equal-to 0.20-0.25 electrons/formula unit).