The effect of isoelectronic substitutions on the microscopic properties of LaFe1−xRuxAsO, for 0< x< 0.8, has been investigated by means of μSR and 139La NMR. It was found that Ru substitution causes a progressive reduction of the Néel 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 metallic antiferromagnetic ground state, while the other one is characterized by weakly correlated electrons. Ru for Fe substitution yields 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 increasing Ru content 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 magnetic ground state.
Magnetic properties of spin-diluted iron pnictides from μSR and NMR in LaFe1−xRuxAsO
SANNA, SAMUELE;
2012-01-01
Abstract
The effect of isoelectronic substitutions on the microscopic properties of LaFe1−xRuxAsO, for 0< x< 0.8, has been investigated by means of μSR and 139La NMR. It was found that Ru substitution causes a progressive reduction of the Néel 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 metallic antiferromagnetic ground state, while the other one is characterized by weakly correlated electrons. Ru for Fe substitution yields 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 increasing Ru content 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 magnetic ground state.
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