ESR of Gd3+ in Y1-x-yYbxGdyInNi4

Electron spin resonance (ESR) results of Gd3+ diluted in (Y1-xYbx)InNi4 for 0 less than or equal to x less than or equal to 0.8 are reported. It is fo und that for x = 0 the linewidth presents the usual temperature linear beha vior and a negative g-shift. As x is increased the residual linewidth also increases, and a non-linear temperature dependence is observed. An addition al relaxation channel through the RKKY interaction is suggested to explain the results. The Yb exchange parameter is determined as function of the con centration. (C) 2001 Elsevier Science BN. All rights reserved.