Controlled hydrothermal synthesis and magnetic properties of three-dimensional FeSe2 rod clusters and microspheres

In this paper, we report a simple and controllable hydrothermal synthetic approach of FeSe2 microstructures with two different morphologies, namely the relatively anisotropic rods clusters and the relatively isotropic microspheres. The citric acid plays an important role in controlling the shape of FeSe2 microcrystals. The possible growth mechanisms of FeSe2 rods clusters and microspheres are studied on the basis of our experimental observations depending on different reaction conditions (including temperature, time and the amount of the additive) as well as our understandings. The Se–Se stretching modes of FeSe2 microstructures are preliminarily explored by the Raman spectra. These FeSe2 microcrystals also exhibit strongly anisotropy magnetic properties under a magnetic field from −60 KOe to 60 KOe at 4 K.