Structural, electrical and magnetic properties of RE1/3Sr2/3FeO3 compounds (RE = La, Pr, Nd, Eu and Gd)

Abstract

We report results of structural, magnetic and electrical measurements performed on the perovskite RE1/3Sr2/3FeO3 compounds (RE = rare earth). Samples with light RE (La, Pr or Nd) show a metal-insulator-like transition coupled to an antiferromagnetic ordering upon cooling. This transition is believed to be brought about by a charge ordering of Fe3+ and Fe5+ions in the low temperature phase accompanied by the concomitant structural transition. The replacing of light RE by heavy ones (Gd or Eu) gives rise to high-resistivity compounds with no metal-insulator transition. However, the magnetic transition remains at low temperatures. A previous Mössbauer study reports similar behaviour for RE=Eu compound. This suggests that variations in Mössbauer spectra may be of a magnetic origin in light RE compounds and not coming from a full charge disproportionation of Fe4+ as deduced previously.