Magnetic-field and pressure dependence of low-temperature resistivity in UGe2

We report measurements of resistivity ρ in UGe2 at temperatures T down to 0.3 K, pressures P up to 19.8 kbar, and magnetic fields Bappl up to 17.5 T applied along the magnetic easy a axis. The coefficient A of the T2 term of ρ(T) is determined as a function of Bappl and P. In the large-moment ferromagnetic phase (the low-P high- Bappl phase), A is found to be a function of the single parameter (Bappl - Bx) and approximately obeys a power law A (Bappl - Bx) -1 2, where Bx is the transition field from the small- to the large-moment ferromagnetic phase. The T dependence of ρ at fields just above Bx suggests a contribution to ρ from excitations with a gapped spectrum.