Microwave surface resistance of HgBa2CaCu2O6+δ thin films

Abstract

Microwave surface resistance (Rs) has been measured on c-axis-oriented superconducting HgBa2CaCu2O6+δ (Hg-1212) films. A cavity perturbation method was employed using a high-Q Nb cavity cooled at 4.2 K. For the best film, an Rs as low as ∼0.3 mΩ was observed at 10 GHz up to ∼120 K on Hg-1212 films that have smooth surface morphology and high critical current density near 2 MA/cm2 at 100 K and self-field. This result suggests that Hg-1212 films are very promising for microwave applications above 100 K.