ROLES OF THE ORDER PARAMETERS M AND MS IN THE MAGNETOSTRICTION OF DY3AL5O12(DAG)

An analysis has been made of the dependence of the magnetostrictive distortion of DAG on the two order parameters M and Ms. This paper is a brief report of the analysis and of experiments which test the analysis. The ten cases considered included ? parallel to each of the principal directions with gauges parallel, perpendicular and in some cases oblique to the field directions. All cases are predicted to contain terms in M2 and M s2. In four there is an additional term in MsM. Previous work has put at our disposal techniques for setting Ms to either of the time reverse antiferromagnetic states A+ and A -. Thus we can test whether or not δl/l has a component odd in M and Ms. Experiments on all geometries give results consonant with the theory. In addition, there are two anomalous results which we believe to be artifacts.