Heat capacity and neutron diffraction studies on the frustrated magnetic Co<sub>2sub>(OH)(PO<sub>4sub>)<sub>1鈭?span style='font-style: italic'>xsub>(AsO<sub>4sub>)<sub>xsub> [0鈮?span style='font-style: italic'>x鈮?] solid solution
- 作者：I. de Pedro<sup>asup><sup> ; sup><sup>bsup><sup> ; sup><sup>depedrovm@unican.essup> ; J.M. Rojo<sup>bsup> ; J. Rodrí ; guez Ferná ; ndez<sup>asup> ; J. Sanchez Marcos<sup>asup><sup> ; sup><sup>1sup> ; M.T. Ferná ; ndez-Dí ; az<sup>csup> ; T. Rojo<sup>bsup>
- 关键词：Insulation compounds ; Magnetic structures ; Neutron diffraction ; Specific heat ; Magnetostructural correlations
- 刊名：Journal of Solid State Chemistry
- 出版年：2012
- 期刊代码：130_00224596
- 类别：ch
- 出版时间：April, 2012
- 卷：188
- 期：Complete
- 页码：1-10
- 文件大小：1638 K
摘要
The Co<sub>2sub>(OH)(PO<sub>4sub>)<sub>1鈭?em>xsub>(AsO<sub>4sub>)<sub>xsub> [0鈮?em>x鈮?] solid solution exhibits a complex magnetic behaviour due to the bond-frustration in its magnetic structure. Heat capacity measurements of the (x=0.1-0.5) phases show a three-dimensional magnetic ordering (位 anomaly) that shifts to lower temperatures and becomes broader as the AsO<sub>4sub><sup>3鈭?/sup> content increases. For x=0.75, no significant feature was observed whereas for higher arsenate ion content, x=0.9 and 1, a small maximum was detected. The magnetic structures of solid solution are consistent with the existence of predominant antiferromagnetic superexchange interactions through the |OH| and |XO<sub>4sub>| (X=P and As) groups between the Co<sup>+2sup> ions. The substitution of PO<sub>4sub><sup>3鈭?/sup> by AsO<sub>4sub><sup>3鈭?/sup> anions by more than 90%substantially modifies the magnetic exchange pathways in the solid solution, leading to an incommensurate antiferromagnetic structure in Co<sub>2sub>(OH)(PO<sub>4sub>)<sub>1鈭?em>xsub>(AsO<sub>4sub>)<sub>xsub> [x=0.9 and 1] phases.