Synthesis of metastable B2-type Fe–Sn alloy epitaxial films and study of their magnetic properties.

The metastable phases of Fe_1−xSn_x alloys were stabilized by their epitaxial growth on MgO(100). The Fe_1−xSn_x alloys with a body-centered-cubic-based structure were realized in the range of 0 ≤ x ≤ 0.4. For x = 0.25, the B2 structure was observed by transmission electron microscopy and X-ray diffraction analysis, although the hexagonal D0₁₉ structure was a thermodynamically stable phase. With respect to magnetic properties, all the compositions show similar hysteresis curves except for x = 0.25. According to ab initio calculations, D0₃-Fe₃Sn and B2-Fe₃Sn have band structures similar to that of Fe, which results in a large tunnel magnetoresistance by coherent tunneling. [ABSTRACT FROM AUTHOR]