PROCEEDINGS OF THE XIII FEOFILOV SYMPOSIUM "SPECTROSCOPY OF CRYSTALS DOPED BY RARE-EARTH AND TRANSITION-METAL IONS"

Crystal field effects in rare-earth ferroborates R Fe 3 (BO 3 ) 4 with various rare-earth elements are stud- ied theoretically. The rare-earth magnetoelastic interaction Hamiltonian is written in a multipole approxima- tion. The field and temperature dependences of the multipole moments and strain susceptibilities of rare-earth ions in the ferroborate structure are calculated. A comparative analysis of anomalies in the thermal expansion and elastic constants of rare-earth ferroborates with Tb and Dy ions having identical magnetic structure but dif- fering in the degree of anisotropy of the rare-earth ion is performed.