Effect of different surfactants on the morphology, growth and magnetic behavior of MnWO4 crystals via the hydrothermal method

MnWO4 nano- and microcrystals with various morphologies have been prepared by the surfactant-assisted hydrothermal method. The crystals were characterized by X-ray diffraction, scanning electron microscopy and magnetic measurements. Different morphologies and growth mechanisms of MnWO4 crystals depend on the surfactant employed. Our results reveal that the MnWO4 nanocrystals exhibit weak ferromagnetism at low temperature due to incomplete spin compensation on the surface with nanoparticle size, while microflowers show antiferromagnetic behavior at low temperature. The crystal morphologies and the size effects associated with surfactants result in these tunable magnetic behaviors.