Structure and magnetism of semiconductor crystals of the (Ga$_{1-x}$Mn$_x$)$_2$Se$_3$ ($x$ = 0–0.04) compounds

Neutron diffraction and magnetic measurements have been used to study the effect of doping with Mn$^{3+}$ ions on the fine crystal structure of the Ga$_2$Se$_3$ monoclinic compound. It has been established that the structural state of the crystals is changed even at a relatively low doping level ($x$ = 0.04). Arguments in favor of the fact that local Jahn-Teller distortions are responsible for the formation of the fine structure and magnetism in compounds of this class are presented.