Magnetism and Superconductivity in LCMO/YBCO bilayers

Superconductivity, which describes the phenomenon whereby electricity can flow without resistance, occurs in a wide range of materials, but normally only at very low temperatures. Even the so-called high-temperature superconductors need to be cooled down, for example with liquid nitrogen, before they start to superconduct. However, these high-temperature superconductors, first discovered more than 20 years ago, continue to intrigue us. In particular, it is thought that if we can understand why these materials superconduct then it might be possible one day to design a material which will superconduct at room temperature. However, no such theory has been accepted. One of the most intriguing things is the close-relationship of the superconducting state to magnetism, and many believe that magnetism might be the glue that bindsthe superconducting electrons together. The interaction of magnetism with superconductivity can usefully be investigated by forcing magnetic and superconducting structures together by growing thin films of superconducting and ferromagnetic layers on top of each other. Then the interactions and effects of one on the other can be studied by various techniques, one of which is by looking at how x-rays are absorbed depending on the magnetism in the sample.A synchrotron is a device for producing intense x-rays which can in turn be used to probe materials. The current proposal seeks funding for an experiment which has been given peer-reviewed beamtime at a synchrotron in Japan (called SPring-8), and also to visit the Department of Physics at the University of Kyoto, where Dugdale has been invited to give a seminar, in order to develop collaborative links.