Cation Sublattice Disorder Induced by Swift Heavy Ions in MgAl2O4 and ZnAl2O4 Spinels: 27Al Solid-State NMR Study

详细信息    查看全文

• 作者：Nadia Pellerin ; Catherine Dodane-Thiriet ; Val&eacute ; rie Montouillout ; Michel Beauvy ; Dominique Massiot
• 刊名：Journal of Physical Chemistry B
• 出版年：2007
• 出版时间：November 8, 2007
• 年：2007
• 卷：111
• 期：44
• 页码：12707 - 12714
• 全文大小：217K
• 年卷期：v.111,no.44(November 8, 2007)
• ISSN：1520-5207

文摘

MgAl₂O₄ and ZnAl₂O₄ spinels have been irradiated by swift heavy ions (⁸⁶Kr and ³⁶S) simulating the irradiationby fission products for applications in the transmutation targets. The structures of unirradiated and irradiatedspinel samples have been studied by NMR spectroscopy, with ²⁷Al magic angle spinning and multiple-quantummagic angle spinning experiments. The parameters of fluence and electronic stopping power have beencompared. For ⁸⁶Kr ions, the obtained spectra are modified by irradiation: we observe a rise of the amountof aluminum in tetrahedral sites and a widening of the lines associated with the different aluminum environmentscompared with those of the pristine samples. Site exchange in the cationic sublattice is then observed and canbe quantified from NMR spectra, determining the inversion parameter. An inversion parameter of 0.77 isestimated for the MgAl₂O₄ spinel irradiated with 10¹³ Kr ions/cm², for a value of 0.275 in the pristine samples.Moreover, a line attributed to aluminum in 5-fold coordination with oxygen is observed in irradiated spinelsamples at the maximum fluence for krypton. These new aluminum environments can characterize a transitionlayer which could change toward an amorphous layer, increasing the electronic stopping power and/or thefluence.