Magnetic properties and interactions in the RMn12-xFex series (R = Y, Ho, Er, Nd; x <= 9) - art. no. 144426

Powder neutron thermodiffraction studies have allowed a precise determinati on of the magnetic phase diagrams of the RMn12-xFex series (ThMn12 structur e) with the occurrence of two different ordering temperatures T-N and T-C c orrelated, respectively, to anti ferromagnetic and ferromagnetic couplings. At low iron contents (x less than or equal to5) and for all R elements, th e 3d metal sublattices exhibit antiferromagnetic (AF) configurations lying in the basal plane (a, b). The R magnetic moments order ferromagnetically a t very low temperature only with c as an easy axis. For higher iron concent rations, the 3d magnetic moment arrangements change progressively with ferr omagnetic (F) components collinear with the c axis superimposed on the AF c omponents. For x>6, the Curie temperature T-C coming from the F components of the 3d and R sublattices increases markedly. In addition, T-N and the 3d AF components both decrease with x.