Neutron diffraction study of cobalt-doped YbFeO3

YbFeO3 belongs to the family of orthoferrites which show weak ferromagnetic properties because of canted antiferromagnetic ordering. Measurements of nuclear and magnetic structure factors on a single crystal sample of YbFeO3 doped with 9% cobalt. Intensities of 75 purely nuclear reflections, mostly from [001] zone have been used to determine the atomic coordinates by the least squares refinement technique. 36 magnetic reflections have been measured in [100] and [010] zones up to sinO/lambda = 0.67 A-1. At room temperature only the Fe moments are ordered and hence an analysis of the experimental data has straightway given the form factor of Fe3+ ions in octahedral environment. This has been compared with other experimental and calculated Fe3+ form factors. Substitution of Fe by a small amount of Co does not have any appreciable effect on the atomic coordinates, but the magnetic properties are drastically altered