Temperature effects on the structure and morphology of Nd:YAG nanocrystallites

In this article, we report that it is possible to synthesize Nd:YAG nanoparticles with sizes as low as 50 nm and with much lower agglomeration by modified co-precipitation methods. This is the main advantage of these methods, in compare with the time consuming standard co-precipitation method, which synthesize particles with sizes in the range of 100 nm. Other advantages of the present methods include the omission of 700 °C calcinations processes which decrease the grain sizes. In addition, in our modified methods, the second high temperature calcination is eliminated without having any effect on the grain sizes and structure of the final powders. XRD patterns reveal that in heating processes no crystalline structure is formed till 800 °C and from 900 °C the aluminum and yttrium oxides crystallites are obtained from their hydroxides. At higher temperatures and according to the molar ratios of the elements which are present in the reaction, the oxides react with each other and make various compounds of aluminum oxide and yttrium oxide (YAM, YAP and YAG). Back-scattering Raman Spectroscopy, SEM imaging and X-ray diffraction characterizations of the nanocrystallites have been used to study the structure and morphology of the synthesized nanocrystallites. The Raman spectra of the samples heated for 1 hour at 1700 °C show that at this temperature the structure of all powders were converted to YAG.

► YAP – Yttrium Aluminium Perowskite.
► YAM – Yttrium Aluminium Monoclinic.
► SEM – Scanning Electron Microscopy.
► XRD – X Ray Diffraction.