Helicoidal ordering in iron perovskites

TL;DR

This paper investigates magnetic ordering in iron perovskites with negative charge transfer energy, revealing that oxygen hole contributions favor helicoidal spin arrangements over ferromagnetism, with implications for magnetic spectra and pressure effects.

Contribution

It demonstrates that oxygen hole weight influences magnetic ordering, favoring helicoidal structures in certain iron perovskites, a novel insight into their magnetic behavior.

Findings

Helicoidal order is favored over ferromagnetism with high oxygen hole weight.

Magnetic excitation spectra are characterized for these materials.

Pressure impacts magnetic ordering in iron perovskites.

Abstract

We consider magnetic ordering in materials with negative charge transfer energy, such as iron perovskite oxides. We show that for a large weight of oxygen holes in conduction bands, the double exchange mechanism favors a helicoidal rather than ferromagnetic spin ordering both in metals, e.g. SrFeO_3 and insulators with a small gap, e.g. CaFeO_3. We discuss the magnetic excitation spectrum and effects of pressure on magnetic ordering in these materials.