Heat-capacity studies of crystal-field effects in diluteRRh4B4compounds

Specific-heat data are presented for a number of compounds of the form $R_x{\mathrm{Y}}_{1-x}{\mathrm{Rh}}_4{\mathrm{B}}_4$, where $R$ (= Dy, Ho, Er, and Tm) is a rare-earth element and $x=0.1\mathrm{}$. Schottky anomalies arising from crystal-field splittings of the rare-earth ions are analyzed using crystal-field parameters recently determined for Er${\mathrm{Rh}}_4$ ${\mathrm{B}}_4$. Utilizing simple scaling arguments for the crystal-field parameters as the rare-earth ion is changed, a satisfactory explanation of the specific-heat data is obtained.