Metal-insulator transition in Fe-substituted SrRuO3 bad metal system

The effect of Fe substitution in the bad metal SrRuO3 perovskite was studied by resistivity, magnetic susceptibility and Mossbauer spectroscopic measurements. The conduction behavior changed from metallic for x(Fe)less than or equal to0.1 to non-metallic for x(Fe)>0.26. In the intermediate concentration range, 0.1<x(Fe)<0.26, a resistivity minimum was observed as a function of temperature. The magnetic properties showed a change from ferromagnetic to paramagnetic for x(Fe)greater than or equal to0.3. There was an enhancement in quadrupole splitting deduced from Fe-57 Mossbauer spectra in going from compositions x(Fe)<0.3 to x(Fe)greater than or equal to0.3 suggestive of a change in screening of ionic charge at this composition. These observations show that the change in conduction behavior of this system may be related to the initial small mean free path of the bad metal system as well as a change in conduction electron density brought about by substitution of trivalent Fe for quadruvalent Ru. (C) 2003 Elsevier B.V. All rights reserved.