LOW-TEMPERATURE TM-169 MOSSBAUER SPECTRUM OF THE TMBA2CU3O7-DELTA SUPERCONDUCTOR

A Tm-169 Mossbauer effect spectrum at 60 mK of the TmBa2Cu3O7-delta superconductor is a symmetric doublet characteristic of pure quadrupolar interaction. There is thus no evidence of Tm magnetic ordering in this material down to this temperature, in contrast to other rare-earth based "1-2-3" superconductors. The spectrum is fitted with crystal field parameters derived from those of the holmium-based superconductor, and values are found for shielding parameters.