Spin Glass Behavior in the Dy3-xYxTaO7 System
  Several x-compositions of the polycrystalline Dy3-xYxTaO7 system, crystallizing in the weberite-type structure, were synthesized and structurally characterized using Rietveld refinements based on X-ray diffraction data. In previous magnetic characterization of Dy3TaO7 (x = 0), with the same crystal structure, an antiferromagnetic transition at T = 2.3 K has been assigned to this compound. On the basis of DC and AC magnetic susceptibilities analyses, we show in this work that all compounds in the x range of 0-1.0 exhibit a spin glass behavior. The nature of the spin glass behavior in Dy3-xYxTaO7, can be attributed to the highly frustrated antiferromagnetic interaction of the Dy3+ sublattice and to the Dy3+-Dy3+ distorted tetrahedra array in the weberite-type structure of this system. By fitting AC susceptibility data, using dynamical scaling theory equations, we conclude that a cluster spin glass is present in Dy3-xYxTaO7 in the low temperature range. Depending on the x-composition, Tg ~ 2.2 - 3.2 K. In the range 15-300 K the system obeys a Curie-Weiss magnetic behavior. 
J. Francisco Gomez-Garcia, Roberto Escudero, Gustavo Tavizon
cond-mat.mtrl-sci