Quadrupole Interaction of 99Ru in Pr,Nd and 100Rh in Tb Hosts

The electric field gradient at transition element impurities ⁹⁹Ru and ¹⁰⁰Rh in metallic rare earth hosts Pr, Nd and Tb has been investigated by time differential perturbed angular correlation (TDPAC) technique at room temperature. The electric field gradients, calculated from the measured quadrupole interaction frequencies at room temperature, are; RuPr: 6.06×10¹⁷ V/cm², RuNd: 5.83×10¹⁷ V/cm² and RhTb: 5.40×10¹⁷ V/cm². The electronic enhancement factors (α) for RuPr and RuNd are about 2.5 times the value observed in RuGd and RhTb (it is found to be more than 40 as in RhGd). The results cannot be explained in terms of the existing models based on charge transfer or volume mismatch of the impurity and the host. This revised version was published online in September 2006 with corrections to the Cover Date.