DOPING AND PRESSURE STUDY OF U3SB4PT3

The effects of doping and pressure on the U3Sb4Pt3 system have been studied. Substitution of either trivalent yttrium or lutetium for uranium causes significant changes in the temperature dependences of the electrical resistance and of the magnitude of the linear coefficient of the specific heat gamma. However, substitution of tetravalent thorium causes little change in gamma, even though it affects the electrical resistance in a manner similar to that seen in the cases of lutetium and yttrium. Finally, application of hydrostatic pressures up to 16.5 kbar causes no significant change in the electronic gap deduced from the electrical resistance.