Ferromagnetic spin-order in Mg-doped SnS2 nanoflowers prepared by hydrothermal method

• Pure and Mg-doped SnS2 nanoflowers were synthesized via the hydrothermal method.
• Substituted Mg can red-shift the band-gap and enhance the ferromagnetism.
• The ferromagnetic coupling is attributed to a p–p coupling interaction.
• Interstitial Mg destroys the ferromagnetism due to the holes compensation effect.

Mg-doped SnS2 nanoflowers were synthesized by hydrothermal method. The XRD and absorption spectra analyses reveal that the incorporated Mg atoms substitute for Sn atoms in SnS2 lattice and red-shift the band-gap at low doping concentration (≤4 at%). With further doping, a transformation of Mg atoms from substitutional sites to interstitial sites occurs. The ferromagnetism of SnS2 nanoflowers is enhanced non-monotonously with Mg doping and the largest saturation magnetization of 2.11×10−3 emu/g appears in 4 at% Mg-doped SnS2. The holes created by Mg substituted incorporation may be the origin of the ferromagnetism. On the other hand, interstitial Mg atoms play a negative role in enhancing the ferromagnetism due to the holes compensation effect.