Departamento de Química Inorgánica, Facultad de CC Químicas, U Complutense de Madrid, Madrid, Spain.
J Phys Condens Matter. 2013 Apr 24;25(16):165704. doi: 10.1088/0953-8984/25/16/165704. Epub 2013 Apr 3.
A detailed study of the structure and properties for the as-prepared and oxygen annealed Mo0.3Cu0.7Sr2TmCu2Oy material is reported. The Cu/Mo cationic distribution is established using a combination of x-ray/neutron powder diffraction refinement. The chemical substitution of the Mo ions for the Cu ions in the CuYSr2Cu2O(7-δ) structure is found to occur in both of the copper sites for the as-prepared sample. Interestingly, no trace of Mo substitution in the copper plane site is found to occur after oxygenation. The as-prepared Mo0.3Cu0.7Sr2TmCu2Oy material is found to be a spin glass (SG) system and explained on the basis of the cluster-by-cluster freezing model. On the other hand, the oxygen annealed material is superconducting (SC) (T(SC,onset) = 31 K). A peak has been observed in the critical current density plot and can be explained on the basis of field induced pins. The influence of oxygen annealing in the structure and properties of this material are presented and discussed. This seems to be the first case of a SG-SC transformation following an oxidation reaction in cuprates.
本文详细研究了制备态和氧退火的 Mo0.3Cu0.7Sr2TmCu2Oy 材料的结构和性能。通过 X 射线/中子粉末衍射精修的组合，确定了 Cu/Mo 阳离子的分布。在 CuYSr2Cu2O(7-δ)结构中，发现 Mo 离子对 Cu 离子的化学取代同时发生在两个铜位，在氧合后，在铜面位没有发现 Mo 取代的痕迹。制备的 Mo0.3Cu0.7Sr2TmCu2Oy 材料被发现是一种自旋玻璃 (SG) 系统，并基于簇对冻结模型进行了解释。另一方面，氧退火的材料是超导的 (SC) (T(SC,onset) = 31 K)。在临界电流密度图中观察到一个峰值，可以根据磁场诱导的钉扎来解释。本文介绍和讨论了氧退火对该材料结构和性能的影响。这似乎是首例在铜酸盐中氧化反应后发生 SG-SC 转变的情况。
