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We present our femtosecond optical pump-probe studies of proximized ferromagnet-superconductor nanobilayers. The weak ferromagnetic nature of a thin NiCu film makes it possible to observe the dynamics of the nonequilibrium carriers through the near-surface optical reflectivity change measurements. The subpicosecond biexponential reflectivity decay has been identified as electron-phonon Debye and acoustic phonon relaxation times, and the decay of Debye phonons versus temperature dependence was used to evaluate the electronphonon coupling constants for both the pure Nb and proximized Nb/ NiCu heterostructures down to low temperatures. We have also demonstrated that the NiCu overlay on top of Nb dramatically reduced the slow, bolometric component of the photoresponse component, making such bilayers attractive for future radiation detector applications.

There are high expectations for coated conductors in electric power applications such as superconducting magnetic energy storage (SMES) systems, power cables, and transformers owing to their ability to contribute to stabilizing and increasing the capacity of the electric power supply grid as well as to reducing CO 2 emission as a result of their high critical-current characteristics. Research and development has been performed on wires/tapes and electric power devices worldwide. The Materials and Power Applications of Coated Conductors (M-PACC) Project is a fiveyear national project in Japan started in 2008, supported by the Ministry of Economy, Trade and Industry (METI) and the New Energy and Industrial Technology Development Organization (NEDO), to develop both coated conductors that meet market requirements and basic technologies for the above-mentioned power applications using coated conductors. In this article, research and development results are reviewed and compared with the interim/final targets of the project, and future prospects are discussed. #

Ultrafast voltage transients from optically thick YBa 2 Cu 3 O 7−x (YBCO) microbridges, dc-biased and triggered with femtosecond optical pulses at temperatures below the YBCO critical temperature were used to excite radiation of a transmitting gigahertz-frequency antenna. The shape of the power spectrum of the antenna radiation depended on the time evolution and amplitude of the YBCO photoresponse transient, which was controlled by the incident laser fluence and the microbridge temperature and bias current. The main contribution to the above 10 GHz radiation was attributed to the photoresponse rising edge, generated due to the initial supercurrent redistribution and the kinetic-inductive effect. Low-frequency antenna radiation was excited by the photoresponse component associated with heating and cooling effects generated in the superconducting microbridge. Our antenna radiation approach can be used for time-resolved investigation of electric current distributions in photoactivated YBCO thin films.