Neutron-Scattering Study of Fe-Substitution Effect on the Static Spin Correlation in La2-xSrxNiO4

Abstract

We have performed elastic neutron scattering measurements on the Fe-doped La 2- x Sr x NiO 4 (LSNO) with 0.12 ≤ x ≤0.50 to study the magnetic impurity effects on the static spin correlations. In the pristine LSNO system, it is well known that both spin and charge stripe orders are stabilized at low temperatures in the wide hole concentration range from 0.12 to 0.70. The incommensurability (e) increases upon Sr-doping and tends to saturate with e max ∼0.47 (r.l.u.) for x > 0.5. We found that 4% Fe-substitution for Ni ion reduces e at the fixed Sr concentration for the all measured samples with 0.12 ≤ x ≤0.5. The e in the Fe-substituted samples with x = 0.25, 0.33, 0.37, and 0.50 was 0.02–0.04 (r.l.u.) smaller than that in the pristine samples. Furthermore, we observed commensurate peak in the Fe-doped x = 0.12 sample. No well-defined incommensurate magnetic peaks were detected, unlike to the result for the pristine x = 0.12 sample. The effect of Fe-substitution on the magnetic ordering temperature ( T spin...