  We report the discovery of a giant out-of-plane coercivity in the Fe-doped
Mn3Sn single crystals. The compound of Mn2.42Fe0.58Sn exhibits a series of
magnetic transitions accompanying with large magnetic anisotropy and electric
transport properties. Compared with the ab-plane easy axis in Mn3Sn, it
switches to the c-axis in Mn2.42Fe0.58Sn, producing a sufficiently large
uniaxial anisotropy. At 2 K, a giant out-of-plane coercivity (Hc) up to 3 T was
observed, which originates from the large uniaxial magnetocrystalline
anisotropy. The modified Sucksmith-Thompson method was used to determine the
values of the second-order and the fourth-order magnetocrystalline anisotropy
constants K1 and K2, resulting in values of 6.0 * 104 J/m3 and 4.1 * 105 J/m3
at 2 K, respectively. Even though the Curie temperature (TC) of 200 K for
Mn2.42Fe0.58Sn is not high enough for direct application, our research presents
a valuable case study of a typical uniaxial anisotropy material.
