作者: J Francisco Gomez-Garcia , Roberto Escudero , Gustavo Tavizon
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摘要: Several x-compositions of the polycrystalline Dy3-xYxTaO7 system, crystallizing in the weberitetype 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 range of 0≤ x≤ 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.