Band filling versus bond bending in substituted L_(x)Sr_(2-x)FeMoO_(6) (L=Ca, La, Nd) compounds

摘要

With the aim of determining and discriminating the influence of both steric and band-filling effects on the strength of the magnetic interactions of double perovskites, we have studied the structural and magnetic properties of substituted L_(x)Sr_(2-x)FeMoO_(6) (L=Ca, La, and Nd) compounds. Our results show that the raising of Curie temperature in electron-doped samples (La and Nd substitutions) is mainly due to band-filling effects, being the influence of structural distortions (steric effects) is of less relevance. This fact contrasts with the well-known properties of manganites, where a strong correlation between structural properties and magnetic interactions is present. We argue that this disagreement relies on the different symmetries of the electronic orbitals involved in the magnetic interactions in both cases.