Magnetic penetration depth in RbOs2O6 studied by muon spin rotation -: art. no. 104504

Measurements of the magnetic field penetration depth lambda in the pyrochlore superconductor RbOs2O6(T-c similar or equal to 6.3 K) were carried out by means of the muon-spin-rotation (mu SR) technique. At low temperatures lambda(-2)(T) saturates and becomes constant below T similar or equal to 0.2T(c), in agreement with what is expected for weak-coupled s-wave BCS superconductors. The value of lambda at T=0 was found to be in the range of 250-300 nm. mu SR and equilibrium magnetization measurements both reveal that at low temperatures lambda is almost (at the level of 10%) independent of the applied magnetic field. This result suggests that the superconducting energy gap in RbOs2O6 is isotropic.