Structural and Magnetic Properties of Mn$_{1.5}$X$_{0.5}$Sn (X $=$ Cr, Mn, Fe, Co) Melt-spun Ribbons*

Mn$_{1.5}$X$_{0.5}$Sn (X $=$ Cr, Mn, Fe, Co) nanomaterials in a hexagonal Ni$_{2}$In-type crystal structure have been prepared using arc-melting and melt spinning. All the samples show moderate saturation magnetization at 100 K with a highest value of 458 emu/cm$^{3}$ for Mn$_{1.5}$Fe$_{0.5}$Sn, but their Curie temperatures (Tc) are less than 300 K. The highest Tc is 206 K for the Fe containing sample. All samples except the Cr containing one show irreversibility between the zero-field-cooled and field-cooled measurements at the low temperature, showing a spin reorientation or spin-glass-like behavior. The magnetic anisotropy constants calculated at 100 K are on the order of 1 Merg/cm$^{3}$. The magnetic properties of these materials have substantially improved due to vacuum annealing, where the Tc for Mn$_{2}$Sn annealed at 450 $^{\circ}$C has increased by about 75 K from 190 K to 265 K.