Crystallographic and Magnetic Properties of CuRh2 Se,-FeRh2 Se, Series

金哲聖(Chul-Sung Kim) ； In-Bo Shim

《Chinese Journal of Physics》 28卷1期 (1990/02) Pp. 15-27

並列摘要

The mixed series CuRh2Se4 – FeRh2Se4 has been synthesized and studied by x-ray, Mossbauer, and magnetic measurements at temperatures between 4.2 and 300 K. We found that the crystal structure of FexCu1-x Rh2Se4 is transformed from spinel to monoclinec structure as iron concentration increases. The isomer shift measurements indicated that the charge state of the Fe ions undergoes gradual change from ferric to ferrous iron as x is increased. The origin of this transition seems to be in the-change of ionic radius of iron ions from smaller one of Fe' to large one of Fe^2+. All the samples become antiferromagnets. FeRh2 Se, has been synthesized and the crystal structure is found to be monoclinic with the lattice parameter: a = 6.310 Ǻ, b = 3.643 Ǻ, c = 11.14 Ǻ, Ǻ,β= 92.42'. The structure is characterized by ordered vacancies in alternate metal layers. The iron ions are found to be ferrous in charge state and occupy the metal layers which are without vacancies, which is ”inverse” to the site distributions reported for similar structures.