Single Crystal Neutron Diffraction Study of SrFeO3-x(x=0.1)

Neutron diffraction study was carried out on single crystals of the perovskite oxide SrFeO 3- x ( x =0.1). SrFeO 3- x ( x =0.1) has a proper screw spin structure with the propagation vector parallel to [111] direction and its Néel temperature is 118 K. The electron configuration of Fe 4+ (3 d 4 ) ion is close to the low-spin state ( t 2 g 4 ) and the oxygen ion has the unpaired electron with the magnetic moment of 0.3µ B antiparallel to the vector sum of the magnetic moments of two iron ions lying on the neighbouring planes perpendicular to the screw axis. The absolute value of the propagation vector is almost constant, \(0.130{\times}\surd{3}{\cdot}2\pi\)/a Å -1 , at temperatures below 50 K, while it decreases gradually at higher temperatures reaching \(0.118{\times}\surd{3}{\cdot}2\pi\)/a Å -1 at T N .