The effect of Al doping on the structure and magnetism in cobaltite CaBaCo₄O₇

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• 作者：Youming Zou ; Zhe Qu ; Lei Zhang ; Wei Ning ; Langsheng Ling ; Li Pi ; Yuheng Zhang
• 关键词：A. Magnetically ordered materials ; C. Phase transitions
• 刊名：Journal of Alloys and Compounds
• 出版年：2013
• 出版时间：5 November, 2013
• 年：2013
• 卷：576
• 期：Complete
• 页码：1-4
• 全文大小：761 K

文摘

We report the effects of Al-doping on the structure and magnetic properties in CaBa (Co_1?xAl_x)₄O₇ (0 ? x ? 0.25). The system exhibits a structural transition from an orthorhombic symmetry to a hexagonal symmetry when the Al content exceeds x = 0.1. The Curie temperature and the value of the magnetization decrease with increasing Al doping level, indicating that the ferrimagnetic ground state is gradually suppressed. The ground state eventually transits into a spin-glass state for x > 0.1. Moreover, the short-range magnetic correlations, which occur at high temperatures in CaBaCo₄O₇, are found to be gradually suppressed with increasing Al content and eventually disappear for x = 0.25. By comparing our results with other Co-site doping cases, we suggest that the lattice and the spin degrees of freedom are relatively decoupled in CaBaCo₄O₇.