Optical investigation of the spin-wave spectrum in the weak ferromagnet CoCO3

The fine structure of light absorption in the weak ferromagnet CoCO3 is investigated. The magnetic dipole line detected at the frequency 22860 cm−1 is identified as an exciton line, while the electric dipole bands at 22893.5, 22905,and 22928 cm−1 are identified as “cold” and at 22810 and 22828 cm−1 as “hot” magnon satellites. The magnon boundary energy for different points of the Brillouin zone, 33.5 and 22 cm−1, is determined by means of the frequency interval between the exciton line and its magnon satellites.