U.S.-Japan Short-Term Visit: High -Tc Superconductors and other Spin-Gap Magnetic Systems

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0314058UemuraThis award supports a three-month collaborative research project between Professor Yasutomo Uemura at Columbia University in New York and Professor Shin-ichi Uchida at the University of Tokyo in Japan. They will be undertaking research on High-Tc Superconductors and other Spin-gap Magnetic Systems. They will be collaborating on the muon spin relaxation, transport and optical measurements of high-Tc cuprate superconductors (HTSC). Muen spin relaxation is a powerful probe of magnetism and superconductivity. It is sensitive to spin fluctuations in a wide range of frequencies, and spin freezing of periodic/random/dilute spin configurations with an average ordered moment. It also provides volume-differential information for systems with coexisting regions with/without spin freezing. Magnetic field penetration depth of type-11 Superconductors can be determined accurately by muon spin relaxation. The collaborators will work on analyses of existing data. The experimental results will be compared to detailed computer simulation to estimate the volume fraction of the specimen subject to static spin freezing in high magnetic field. In addition to the effect of applied magnetic field as a single perturbation, they will also study what would happen when a high magnetic field is applied to systems which are already subject to other perturbations, such as Zn-doping or magnetic nano-island formation. The project brings together the efforts of two laboratories that have complementary expertise and research capabilities. The U.S. researcher provides expertise in the data analyses and interpretations and the Japanese collaborator is a world leader in optical and transport physics. Superconducting materials are fertile areas for research crucial to a number of applications areas such as the transmission of electricity, advanced electric motors, the storage of energy via flywheels, and advanced opto-electronic devices and sensors. Through the exchange of ideas and technology, this project will broaden our base of basic knowledge and promote international understanding and cooperation. Results of the research will be disseminated at scientific meetings and in scientific journals.