The ac susceptibility and de Haas-van Alphen (dHvA) effect in UGe2 are measured at pressures P up to 17.7 kbar for the magnetic field B parallel to the a axis, which is the easy axis of magnetization. Two anomalies are observed at Bx(P) and Bm(P)(Bx>Bm at any P), and the P-B phase diagram is presented. The Fermi surface and quasiparticle mass are found to vary smoothly with pressure up to 17.7 kbar unless the phase boundary Bx(P) is crossed. The observed dHvA frequencies may be grouped into three according to their pressure dependences, which are largely positive, nearly constant, or negative. It is suggested that the quasi particle mass moderately increases as the boundary Bx(P) is approached. DHvA effect measurements are also performed across the boundary at 16.8 kbar.
|Number of pages||5|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2002 May 1|