Preparation and magnetic properties of CoWO4 nanocrystals

Abstract

Cobalt tungstate (CoWO 4) 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 CoWO 4 sample were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Magnetic measurements on the as-synthesized CoWO 4 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 (MWO 4) materials.