Microwave microstrip resonator measurements of Y1Ba2Cu3O(7-x) and Bi2Sr2Ca1Cu2O(8-y) thin films

Radio frequency (RF) surface resistance measurement experiments on high T(sub c) thin films were performed. The method uses a microstrip resonator comprising a top gold conductor strip, an alumina dielectric layer, and a separate superconductivity ground plane. The surface resistance of the superconducting ground plane can be determined, with reference to a gold calibration standard, from the measured quality factor of the half-wave resonator. Initial results near 7 GHz over the temperature range from 25 to 300 K are presented for YBa2Cu3O(7-x) and Bi2Sr2CaCu2O(8-y) thin film samples deposited by an electron beam flash evaporation process. The RF surface resistance at 25 K for both materials in these samples was found to be near 25 milliohms

Ceramic nitride/metal coatings with enhanced fracture toughness and fatigue resistance using a multiscalar laminate architecture

Ceramic coatings can provide benefits such as improved wear resistance, reduced friction, and be chemical and biological corrosion barriers in various biomedical applications. However long-term issues of film cracking, particle generation, or delamination must be addressed, while achieving decades-long coating lifetimes. Instead of brittle, superhard coatings, softer but tougher coatings achieved with multiscalar, laminate architectures may meet these requirements. Layers of Cr and CrN were combined in multi- and nanolayer structures, and compared to monolayer films. The multiscalar coatings had hardness values lying between the pure Cr and CrN, but higher fracture toughness than the monolayer films