Paramagnetic behaviour in RE_2W_2O_9 tungstates (RE = Pr, Nd, Sm - Gd)

摘要

Magnetic susceptibility measurements revealed a disordered state of magnetic moments above 4.2 K for all compounds under study, a weak response to the magnetic field and the temperature for Sm_2W_2O_9 and Eu_2W_2O_9 tungstates. The temperature independent component of magnetic susceptibility has a positive value for RE_2W_2O_9 (RE = Pr, Nd and Gd) indicating a domination of van Vleck contribution. Only for Gd_2W_2O_9 the magnetization is a universal function of μ_0H/T, characteristic for the superparamagnetism.