Investigation of low-energy electronic excitations in quasi-one-dimensional Ising antiferromagnet CsFeCl3∙2H2O via Raman spectroscopy
V. S. Kurnosov
B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine Kharkiv 61103, Ukraine
Received April 15, 2021, published online May 26, 2021
The frequencies of low-lying electronic excitations in the quasi-one-dimensional antiferromagnet CsFeCl3∙2H2O were determined by Raman spectroscopy. The lowest of them (57 cm−1) was attributed to the magnon-like excitation of the chain of Ising spins of paramagnetic Fe2+ ions. And the next one (77 cm−1) can most likely be attributed to the exciton-like one, associated with the electronic transition to the lower level of the excited orbital quasi-doublet dzx, dzy split by the spin-orbit interaction. Investigations of the splittings and shifts of Raman lines in an external magnetic field allowed us to estimate the values of the magnetic moments of the sublattices in the ground state and to determine their spatial orientation relative to the crystallographic directions.