Synthesis and microwave properties of thin films of the 1 : 2 : 2 : 1 borocarbide superconductors YNiBC and ErNiBC

,High-quality c-axis oriented YNi2B2C (transition temperature T-c=15K) and ErNi2B2C (T-c=9.5K) borocarbide superconducting thin films were grown "in-situ" on MgO and sapphire substrates by planar magnetron sputtering. Here we report data on the temperature, DC and RF magnetic field dependent surface impedance of the films and discuss them in view of possible applications. The YNi2B2C films displayed the behavior expected for BCS-like superconductors, while the microwave response of the antiferromagnetically ordering compound ErNi2B2C mas distinctly different. The field dependent surface resistance of both types of films displayed granular effects.