Alternative approaches used to assess structural changes of natural zircon caused by heat treatment

作者：Huong L T T; Thuyet N T M; Phan T L; Tran N; Toan D N; Thang P D; Huy B T

来源：Physica B: Condensed Matter , 2018, 532: 42-47.

DOI：10.1016/j.physb.2017.03.007

• Zircon
• Heat treatment
• Crystal structure
• Optical and magnetic properties

It is known that large changes in the crystal structure of zircon (ZrSiO4) can be assessed through the linewidth of the characteristic Raman mode (Delta nu(3)) at 1008 cm(-1). However, the use of Delta nu(3) to assess small changes caused by heat treatment at temperatures below its decomposition temperature of similar to 1670 degrees C is difficult. The present work points out that the combination of X-ray diffraction (XRD) analyses, and photoluminescence (PL) and Raman (RS) measurements with different excitation wavelengths is an effective approach to solve the above problem. In this context, we have selected natural zircon containing some rare-earth (RE) impurities, and then studied the changes in its crystal structure caused by heat treatment at temperatures T-an = 400-1600 degrees C. XRD analyses reveal that small modifications of the unit-cell parameters occur as T-an > 600 degrees C. Taking the intensity ratios of the nu(3) mode to RE-related emissions (I nu(3)/I-RE) or the PL intensity ratios between RE-related emissions into consideration, the similar results in good agreement with the XRD analyses are also found. We believe that the small structural changes are related to the migration and redistribution of defects and impurities, and recrystallization of zircon. This could be further confirmed though the relation between paramagnetic and ferromagnetic signals when T-an changes.

• 出版日期2018-3-1