Quantum oscillations near a quantum critical end point in SR3rU2o7

J.-F. MERCURE; A. W. ROST; E. C. T. OFARRELL; S. K. GOH; R. S. PERRY; M. L. SUTHERLAND; S. A. GRIGERA; R. A. BORZI; P. GEGENWART; A. S. GIBBS; A. P. MACKENZIE

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Año: 2010 vol. 81 p. 23510301 - 23510308

1098-0121

We report a detailed investigation of quantum oscillations in Sr3Ru2O7, observed inductively
the de Haas– van Alphen effect and thermally
the magnetocaloric effect. Working at fields from 3 to 18 T allowed us to straddle the metamagnetic transition region and probe the low- and high-field Fermi liquids. The observed frequencies are strongly field dependent in the vicinity of the metamagnetic transition, and there is evidence for magnetic breakdown. We also present the results of a comprehensive rotation study. The most surprising result concerns the field dependence of the measured quasiparticle masses. Contrary to conclusions previously drawn by some of us as a result of a study performed with a much poorer signal-to-noise ratio, none of the five Fermi-surface branches for which we have good field-dependent data gives evidence for a strong-field dependence of the mass. The implications of these experimental findings are discussed.