Electroresistive effect in slightly oxygen deficient Nd0.7Sr0.3MnO3-δ ceramic

We observe a strong electroresistive (ER) effect in slightly oxygen deficient Nd0.7Sr0.3MnO3-delta ceramic which behaves equivalent to the well-known magnetoresistive effect and which apparently involves both the higher insulating grain boundaries as well as parts of the domain (grain) volume, just like the MR in ceramics. While the magnetic field acts on the magnetic dipoles of the manganites (MR), the nature of the electrical dipole moments - intrinsic or extrinsic - is not fully understood as yet, but as the ER-effect increases dramatically with 6, for these compounds the evidence points to extrinsic electrical dipoles which appear together with a local restructuring when oxygen is formally missing. (c) 2005 Elsevier B.V. All rights reserved.