Sharp switching of the magnetization in Fe1 4 Ta S2

Anisotropic magnetotransport measurements are reported on Fe1 4 Ta S2 single crystals grown by vapor transport. Both the magnetization and resistivity are extremely anisotropic, with the magnetic moments aligned parallel to the c crystallographic direction. Fe1 4 Ta S2 orders ferromagnetically below TC =160 K and displays very sharp hysteresis loops in the ordered state for H c. The corresponding magnetoresistance is negative, and it qualitatively reproduces the features observed in the M (H) data by showing a sharp drop around the critical field Hs for the moment reversal. The magnetization switching time shows an unusual increase with increasing temperature. For field applied within the ab plane, the magnetization remains small and linear in field up to 5 T, and the magnetoresistance is positive and quadratic in field, with no visible hysteresis. The squareness of the H c M (H) loops and the high critical field for the magnetization switch (Hs =3.7 T at T=2 K) allow us to classify Fe1 4 Ta S2 as a strong ferromagnet.