Preparation and magnetic properties of CoWO4 nanocrystals

Cobalt tungstate (CoWO₄) nanocrystals with an average size of 20–50 nm were synthesized via a template‐ or surfactant‐free hydrothermal route. The crystal structure and morphology of the as‐synthesized CoWO₄ sample were characterized by X‐ray diffraction, scanning electron microscopy and transmission electron microscopy. Magnetic measurements on the as‐synthesized CoWO₄ nanocrystals indicate a Néel temperature (T_N) of ～40 K. This lower T_N may be a result of the nanostructured particles that reduce the exchange coupling. The new synthetic route presented in this paper has potential applications to fabricate other metal tungstates (MWO₄) materials.