The Gd-Fe exchange interaction in GdFe6Ga6

Abstract We have investigated the Gd–Fe exchange-coupling strength in GdFe 6 Ga 6 by means of magnetization measurements on single-crystalline powder particles that are free to rotate into their minimum-energy direction in the applied magnetic field. The experiments have been carried out at 4.2 K and at high magnetic fields up to 55 T in order to achieve bending of the Gd- and Fe-sublattice moments out of their initially collinear antiparallel configuration. The bending starts around 40 T and, from the magnetization behavior above this field value, the strength of the Gd–Fe exchange coupling J GdFe / k B has been determined to be −8.5 K. This value is discussed and is compared with earlier results on the RFe 6 Ga 6 compounds with R = Dy, Ho, Er and Tm.