QUASIMAGNETIC ORDERING OF PLANAR SPINS IN A RANDOM ANISOTROPY SYSTEM - DY(AS(0.35)V(0.65))O-4

Distortions due to random As/V substitutions in DY(As0.35V0.65)O-4 bre ak local tetragonal symmetry and induce a uniaxial moment parallel to one or the other basal plane axis. This system thus provides an ideal random magnetic anisotropy antiferromagnet with equivalent competing a xes and no dilution of the magnetic ions. Quasielastic neutron-scatter ing experiments of antiferromagnetic ordering at (100) showed a broad peak below 8 K with modest temperature dependence and a narrow peak th at grew rapidly below 1.6 K. The narrow peak implies long range (800 A ngstrom) spin correlations but is never resolution limited, ruling out a conventional magnetic transition. These results are qualitatively c onsistent with predictions of an unusual transition at the lower criti cal dimension for the random anisotropy model.