Low-temperature magnetic structure ofFeSn2

${\mathrm{FeSn}}_2$ is a collinear antiferromagnet between $T_N$=378 K and $T_t$=93 K as shown by previous neutron diffraction and ${}_{}{}^{119}{}_{}{}^{}\mathrm{Sn}$ Mössbauer studies. Below $T_t$, two different noncollinear antiferromagnetic structures are consistent with neutron diffraction results, one, called structure I, being canted along with c axis and the other, denoted structure II, being canted in the basal plane (001) along the [110] direction of the chemical cell of ${\mathrm{FeSn}}_2$. On the other hand, two magnetic structures canted in the basal plane, ${\mathrm{II}}^{\mathrm{a}}$ and ${\mathrm{II}}^{\mathrm{b}}$, which differ only in the propagation vector agree with ${}_{}{}^{119}{}_{}{}^{}\mathrm{Sn}$ Mössbauer spectra. The simultaneous use of the two techniques has allowed an unambiguous choice of structure ${\mathrm{II}}^{\mathrm{a}}$ which is simply characterized by a combination of the magnetic couplings observed in the high-temperature magnetic structures of ${\mathrm{FeSn}}_2$ and ${\mathrm{MnSn}}_2$.