Influence of Ce-substitution on exchange field seen by Gd3+-spin in Gd2−xCexCuO4 compounds

Gd 3+ -EPR linewidth and d.c. magnetic susceptibility are measured in Gd 2−x Ce x CuO 4 compounds with x=0 and 0.15. A step-like rise in the linewidth occurs around the Cu-ordering temperature T N (Cu). The linewidths below and above T N (Cu) are analyzed by using the experimental susceptivility. The result shows that the Cu-ordering modifies the exchange field seen by Gd 3+ -spin.