LINEAR TEMPERATURE-DEPENDENT RESISTIVITY AT CONSTANT VOLUME IN RB3C60

The normal-state electrical resistivity p of the superconductor Rb3C60 has been measured as a function of temperature and hydrostatic pressu re. Under conditions of constant sample volume we find a linear temper ature dependence, rho approximately T, in sharp contrast to rho approx imately T2 observed under conditions of constant sample pressure. The pressure dependence of rho at fixed temperature is exponential, with a reduction in rho by more than 50% for 8 kbar at room temperature. Imp lications for the normal-state scattering mechanism are discussed.