Magnetic properties of spin diluted iron pnictides from muSR and NMR in LaFe1-xRuxAsO

الأصل · EN

The effect of isoelectronic substitutions on the microscopic properties of LaFe1-xRuxAsO, for 0< x< 0.8, has been investigated by means of muSR and 139La NMR. It was found that Ru substitution causes a progressive reduction of the Nèel temperature (Tₙ) and of the magnetic order parameter without leading to the onset of superconductivity. The temperature dependence of 139La nuclear spin-lattice relaxation rate 1/T₁ can be suitably described within a two-band model. One band giving rise to the spin density wave ground-state, while the other one is characterized by weakly correlated electrons. Fe for Ru substitution yields to a progressive decrease of the density of states at the Fermi level close to the one derived from band structure calculations. The reduction of Tₙ with doping follows the predictions of the J₁-J₂ model on a square lattice, which appears to be an effective framework to describe the magnetic properties of the spin density wave ground-state.