Superconducting coplanar waveguide resonators for low temperature pulsed   electron spin resonance spectroscopy
  We discuss the design and implementation of thin film superconducting coplanar waveguide micro- resonators for pulsed ESR experiments. The performance of the resonators with P doped Si epilayer samples is compared to waveguide resonators under equivalent conditions. The high achievable filling factor even for small sized samples and the relatively high Q-factor result in a sensitivity that is superior to that of conventional waveguide resonators, in particular to spins close to the sample surface. The peak microwave power is on the order of a few microwatts, which is compatible with measurements at ultra low temperatures. We also discuss the effect of the nonuniform microwave magnetic field on the Hahn echo power dependence. 
H. Malissa, D. I. Schuster, A. M. Tyryshkin, A. A. Houck, S. A. Lyon
cond-mat.mes-hall cond-mat.other