Electron magnetic resonance imaging of the Fermi surface of Sr₂RuO₄

We have carried out detailed angle dependent studies of the normal state microwave (40-112 GHz) magneto-conductivity of several single crystal samples of the perovskite superconductor Sr₂RuO₄. As previously reported [Phys. Rev. Lett. 84 (2000) 3374], we observe a series of resonant absorptions which we attribute to cyclotron resonance of quasiparticles belonging to the three well-known Fermi surfaces for this material. From the angle dependence, we confirm the two-dimensional character of these resonances, i.e. the cyclotron frequencies scale as the inverse cosine of the angle between the magnetic field and the normal to the conducting layers. Furthermore, by performing measurements on several samples, and in different electromagnetic field configurations, we are able to couple to different cyclotron modes (+ harmonics) which derive from deformations (warpings) of the Fermi surfaces from perfect cylinders. These mode couplings will be discussed in the light of recent angle dependent de Haas-van Alphen measurements.