Magnetic coupling in the tetragonal rare earth iron compounds of the type R(Fe,V) 12

Abstract

The temperature dependence and the field dependence (up to 35 T) at 4.2 K of the magnetization of several compounds of the type RFe 12− x V x , were studied. The magnetic isotherms at 4.2 K as well as the temperature dependence of the magnetization were analysed with a mean field model. The magnetic coupling constant J RT between the moments of the rare earth (R) and 3d (T) element in the Hamiltonian H = − Σ T 2 J RT S R · S T derived from both types of measurements was found to differ considerably. Our results suggest that a mean field model does not lead to a consistent description of all of the magnetic properties if the presence of a magnetic moment on the vanadium atoms is not taken into account.