J. Phys. Colloques
Volume 49, Number C8, Décembre 1988Proceedings of the International Conference on Magnetism
|Page(s)||C8-995 - C8-999|
J. Phys. Colloques 49 (1988) C8-995-C8-999
SPIN GLASS TRANSITION VS STANDARD SCALING LAWS : AN EXPERIMENTAL STUDYJ. J. Prejean1, E. Carré1, P. Beauvillain2 et J. P. Renard2
1 CRTBT-CNRS, BP 166, 38042 Grenoble Cedex, France
2 I.E.F. Bât. 220, Université de Paris-Sud, 91405 Orsay Cedex, France.
We have measured the static non linear susceptibilities a3 (T) and a5 (T) and the a.c. susceptibility of the insulating spin glass : fluorophosphate of Mn. We introduce a criterion for analysing the upper edge τmax of the distribution of the relaxation times. Mainly we find that : (1) a3 (T), a5 (T), τmax vary by orders of magnitude in the 1.08-1.2 Tc range. Each of these quantities is a power of the others in agreement with the standard scaling hypothesis ; (2) a3 (T), a5 (T), τmax can be only interpreted in terms of powers of t = (T - Tc) /T ; (3) no cross over from a high temperature regime to a low temperature one is observed ; (4) the standard power law fits accurately our data of the dynamics with reasonnable values of the parameters in contrast with other recent predictions.