This work was supported by the Deutsche Forschungsgemeinscahnadftb y the NationalS cience Foundationu nder Grant DMR-8313295a nd has benefitedfr om the facilitiesm adea vailablet o the StanfordU niversityb y the NationaSl cienceF ounda-tion-MaterialRs esearchL aboratoriepsr ogramT. he anomaloussc atterinegx perimenwtse rep erformeadt and supportedb y the StanfordS ynchrotronR adia-;