Spectroscopic investigation of some rare earth iron garnets

Optical absorption spectra of Dysprosiumirongarnet (DyIG), Holmiumirongarnet (HoIG) and Erbiumirongarnet (ErlG) have been investigated in the near infrared region at temperatures of 4.2°K and 62°K. Exchange field splittings of the crystal field levels have been observed. — For the three garnets the excited levels of the groundterm up to 110 cm^?1 could be determined. The exchange fields acting on the rare earth ions have been deduced as (305±50)·10³ Oe for DyIG and (284±30)·10³ Oe for ErIG.