Figure 4. Magnetization versus applied field for oriented Fe3Sn powder, and a polycrystalline Fe3Sn sample.
Using the x-ray density of Fe3Sn, the room temperature saturation moment is 1.18 MA/m, or about 2.37 μB/Fe. Noting that the magnetization curves merged together near 3 Tesla, indicates a value for K1 of about 1.8 MJ/m.