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Examines the field performance of a high-resolution nuclear magnetic resonance superconducting magnet. Persistent-mode operation of the magnet; Field decay; Field homogeneity.

The first 920 MHz high-resolution NMR (Nuclear Magnetic Resonance) magnet was successfully installed at the Tsukuba Magnet Laboratory of the National Institute for Materials Science. A persistent operation at 21.6 T has continued since April 2002 without any problems. Excellent field stability of 0.31 Hz/h was observed from December 2002 to January 2003. Since July 2002, the magnet was used as an essential part of the only 920 MHz high-resolution NMR spectrometer in the world. The signal-to-noise ratio of 0.1 % ethylbenzene using a proton-selective probe was as high as 2981. An HCN triple-resonance probe is now attached to the spectrometer to contribute to the National Project on Protein Structural and Functional Analysis in Japan. The completion of the second 920 MHz-class NMR spectrometer is scheduled for spring 2004. [ABSTRACT FROM AUTHOR]

We studied magnetizations of over-doped Bi2Sr2CaCu2O8+y single crystals. The thermoremanent magnetization shows an anomalous random oscillation in low frequency modulation field below 20 K. The result indicates a random motion of the vortices, which suggest there exists a new magnetic phase in the vortex solid phase. [Copyright &y& Elsevier]