SCREW SPIN STRUCTURE IN SrFeO₃

Abstract

Magnetic susceptibility, electric resistivity and neutron diffraction measurements were carried out for the single crystals of SrFeO3-x (x ≈ 0.1). Above the Néel temperature the magnetic susceptibility does not obey the Curie-Weiss law. The activation energy is 0.013 eV. SrFeO3-x (x ≈ 0.1) has the proper screw spin structure with the propagation vector of 0.130 x 2 π/a [111] at liquid helium temperature. An Fe4+ ion has the magnetic moment of 1.6 ± 0.3 µB, which means the electron configuration is close to the low-spin state (t42g). An oxygen ion has the magnetic moment of 0.3 µB antiparallel to the vector sum of the magnetic moments of two iron ions lying on the neighbouring planes perpendicular to the screw axis. The magnetic moment of the oxygen ion is considered to be due to the electron transfer in hybrid Pσ-eg, orbitals.