Abstrakt
Magnetic properties of a tetragonal intermetallic compound GdFe5Al7 have been studied on a single crystal in static magnetic fields up to 14 T. The system is a ferrimagnet (T-C = 265 K) and on this premises we succeeded in describing its low-temperature magnetization curves as well as the temperature dependence of the spontaneous magnetization.
The compound is interesting in two ways: (i) the iron sublattice is diluted so heavily that it is close to the stability limit and cannot be regarded as saturated, (ii) at low temperatures the system is in a state of near compensation, that is, the sublattice moments, albeit distinct, are close in magnitude. The latter has several consequences. (i) The net spontaneous magnetization is small, M-s = 0.58 mu(B)/f.u. at T = 2 K. (ii) The system is in the strong-anisotropy regime despite the weakness of its anisotropy (attributed entirely to the iron sublattice) in energy terms. (iii) A moderate field (similar to 7 T) applied in the easy direction [110] suffices to induce a phase transition into a noncollinear magnetic state.