Microcrystalline Gd 2 MoO 6 prepared by combined mechanochemical/thermal process and its magnetic properties

Gadolinium oxymolybdate, Gd 2 MoO 6 (monoclinic, C 2/ c ) was prepared via nonconventional mechanochemical/thermal process from powdered oxide precursors (Gd 2 O 3 and (NH 4 ) 2 MoO 4 ). The effect of mechanical activation via high-energy ball milling on the reactivity of the stoichiometric Gd 2 O 3 + (NH 4 ) 2 MoO 4 mixture was studied by thermal analysis (TG-DSC) and Fourier-transform infrared spectroscopy. While thermal treatment of nonactivated mixture leads only to decomposition of (NH 4 ) 2 MoO 4 and formation of Gd 2 O 3 –MoO 3 system, mechanical activation provides enough energy for a chemical reaction between both reactants. The product with an average crystallite size of approximately 1 μm shows a well-faceted morphology. The investigation of magnetic properties revealed antiferromagnetic coupling, which is attributed to exchange interactions.