The magnetic properties of Tb(Mn1−xFex)2 solid solutions with 0.35⩽x⩽0.65

Abstract The temperature (4.5–700 K) and magnetic field (0–50 kOe) dependencies of the DC magnetization, and AC magnetic susceptibility (5 Oe, 125 Hz AC field) of the polycrystalline C15 Laves phase Tb(Mn1−xFex)2 alloys with x=0.35, 0.5, and 0.65 have been measured. The substitution of Fe for Mn decreases the lattice parameter. At 5 K, the Tb(Mn1−xFex)2 alloys exhibit a ferrimagnetic state because of the antiparallel alignment of the magnetic moments of Tb and the Fe+Mn atoms. The Curie temperature increases with increasing x, while remanence and coercivity decrease with x at low temperatures, and increase in the high temperature region. A slope change of the inverse DC magnetic susceptibility, χDC−1, was observed for all alloys and the corresponding temperature increases with increasing x. The temperature dependencies of the inverse AC magnetic susceptibility, (χ′AC)−1, exhibit a peak at temperature close to the Curie temperature of each alloy and follow the Curie–Weiss law above this temperature.