Fe2MnSn compound was prepared in the form of polycrystalline ingot by arc-melting. In contrast to the theoretical predictions of stable tetragonal Heusler compound, the material crystallizes in a hexagonal DO19 crystal structure and orders ferromagnetically below T-C = 586(10) K that is only about half of the calculated value of 1012 K.
Magnetic moment 5.87 mu(B) at 10 K is less or about in line with various theoretical predictions. However, electrical resistivity and optical studies reveal no signs of half-metallic behavior predicted theoretically.
The change in the slope of the MOKE spectra below 1.5 eV suggests the main influence of a low energy inter-band transition which points to the loss of half-metallicity in agreement with resistivity and optical measurements.