A novel ferrimagnetic irido-cuprate: IrSr 2GdCu 2O 8

Abstract

We have performed an investigation of the structural, microstructural and magnetic properties of the new compound IrSr 2GdCu 2O 8. The sample was prepared under high temperature (∼1393 K) and high-pressure conditions (∼60 Kbars) in a Belt type apparatus. X-ray diffraction (XRD) analysis shows that this irido-cuprate is isostructural with the corresponding Ru-1212 phase. Structurally, this material shows an interesting hierarchy of ordering phenomena, whose observation actually depends on the technique used to analyze the material: from a “simple” cell a p× a p×3 a p which is supported by XRD, through a “diagonal” one, ∼ 2 a p × 2 a p × 3 a p as seen by SAED, to a microdomain texture of this last one cell supported by HREM. A ferrimagnetic Ir IV–Gd III spin ordering is observed below 15 K. The iridium oxidation state seems to be +4.