Nuclear quadrupole interaction studies of C15 RMn{sub 2} hydrides (R=Y,Gd,Tb,Dy)

The nuclear electric quadrupole interaction (QI) of the probe nucleus {sup 111}In/{sup 111}Cd in the paramagnetic phase of the C15 rare earth (R)-manganese hydrides (deuterides) RMn{sub 2}H(D){sub x}, with R=Y, Gd, Tb, and Dy, has been investigated by perturbed angular-correlation spectroscopy. The QI between the {sup 111}Cd quadrupole moment and the electric-field gradient (EFG) at the probe nucleus on the Mn site has been measured as a function of temperature in TbMn{sub 2}H(D){sub x} in the concentration range 0{ 3.6 the temperature coefficient of the QI is significantly larger than in uncharged RMn{sub 2}. These results are compared with the much stronger concentration dependence and the anomalous temperaturemore » dependence of the QI of {sup 111}Cd in the C15 hydrides HfV{sub 2}H{sub x}. Evidence for an exceptionally high H mobility in TbMn{sub 2}H{sub x} is presented. The measurements provide information on structural changes and magnetic ordering temperatures at different H concentrat0010io.« less