Hydrothermal Synthesis and Magnetic Property of Nanocrystalline Sr-Cr Hydrogarnet

Nanocrystalline Sr-Cr hydrogarnet was synthesized from a relatively mild hydrothermal system. High solubility of the initial of species and highly concentrated mineralizer lowered the crystallization temperature and enhanced the crystalinity. With increasing temperature, OH bondingsto the Sr dodecahecra were broken, and in air or O2, oxidation from Cr(III) to Cr(VI) occurred.Valence variation of the framwork Cr ions determined the decomposition process and the structuraltypes of the decomposition products. Nanocrystalline Sr-Cr hydrogarnet is paramagnetic, and thecomplete quenching of the orbitle monument was observed. Highly symmetric Cr-OH octahedrawere revealed.