The in situ electron-spin resonance of a voltage-biased NbAuNb Josephson junction is reported. The Au barrier is doped with Gd or 167Er ions. Sharp resonances appear in the I-V curves at frequencies equivalent to the crystal-field splitting of AuGd (1.0 and 1.7 GHz) and to the hyperfine splitting of Au167Er (2.87 GHz). The principle of this new type of ESR-Josephson-junction spectrometer, as well as its application, is discussed.
Baberschke, K.; Bures, K. D.; and Barnes, S. E., "ESR in Situ with a Josephson Tunnel Junction" (1984). Physics Articles and Papers. 58.