Magnetic Properties of Sm{sub 0.7}Ho{sub 0.3}Fe{sub 3}(BO{sub 3}){sub 4}

The magnetic properties of a ferroborate single crystal of substituted composition Sm{sub 0.7}H{sub 0.3}Fe{sub 3}(BO{sub 3}){sub 4} with competing Sm-Fe and Ho-Fe exchange interactions are studied. The measured properties and effects are interpreted in terms of a general theoretical approach based on the molecular field approximation and calculations using the crystal field model for a rare-earth ion. The experimental temperature dependences of the initial magnetic susceptibility in the temperature range 2-300 K, the anomalies in the magnetization curves for B Double-Vertical-Line c and B Up-Tack c in fields lower than 1.2 T, and the field and temperature dependences of magnetization in fields lower than 9 T are described. The crystal field parameters and the parameters of the R-Fe and Fe-Fe exchange interactions are determined during the interpretation of the experimental data.