Nanosheets of Metastable and Metamagnetic EuSe₂

We have identified solution conditions for synthesizing the metastable and metamagnetic semiconductor europium dichalcogenide, EuSe₂, as two-dimensional nanosheets. We demonstrated phase control (EuSe or EuSe₂) as well as shape control (blocks or nanosheets) and investigated the mechanism of nanosheet growth. The materials were characterized structurally using powder diffraction and microscopy (scanning electron microscopy, transmission electron microscopy, atomic force microscopy) as well as optical methods (UV-visible spectroscopy and Raman spectroscopy). The most interesting were the anisotropic magnetic nanosheet properties, both χ-(T) and M-(H). Using drop-cast films with high preferred orientation, it was possible to determine differences in the nanosheet magnetic properties both parallel and perpendicular to the plane of the nanosheet (along the c-axis). We observed easy-axis antiferromagnetism along the c-axis and a Néel temperature close to that of the bulk. In addition, the critical field for the metamagnetic transition was reduced compared to the bulk.