Relaxation effects and evidence for one dimensional ordering in KFeCl3 studied by Mössbauer spectroscopy

Mössbauer measurements of KFeCl₃ over the temperature range 4.2–293°K show a transition to a magnetically ordered phase at T_N ? 18.5°K and evidence for one-dimensional order above T_N. In the region 10–25°K striking relaxation effects appear. An approximate analysis of the quadrupole splitting data was used for the determination of the fine structure of the ⁵D levels below T_N which in turn was used for a theoretical reproduction of the relaxation spectra between 10–25°K.