SEMI-SPIN-GLASS AND SPIN-GLASS BEHAVIOR IN EUXSR1-XSE WITH X = 0.5 AND 0.7

We have investigated the linear and, in detail, the non-linear AC susc eptibilities of two insulating spin glasses obtained from the dilution of the antiferromagnetic EuSe with diamagnetic SrSe. The systems stud ied are the mixed compound EuxSr1-xSe with x = 0.5 and 0.7. The linear susceptibilities of the samples show a single peak at their spin-glas s freezing temperatures of 2.00 +/- 0.03 K and 2.88 +/- 0.03 K, respec tively. However, the non-linear susceptibilities (third harmonics) of the systems exhibit double peaks: one at the spin-glass transition tem perature, and the other at a higher temperature somewhat below the Nee l temperature of pure EuSe which is 4.6 K. We believe that the origin of the second peak is the remaining antiferromagnetic phase which seem s to persist in the systems down to a critical concentration below x = 0.5.