Paramagnetic Anisotropy and Crystal-Field Splittings in EuAlO3

The magnetic susceptibilities for orthorhombic EuAl${\mathrm{O}}_3$ have been measured between 1.5 and 300°K. The compound is paramagnetic and shows approximately 20% anisotropy in the susceptibilities below 100°K. The susceptibility along the $b$ axis has a very broad maximum at $T\sim 60$°K. Optical fluorescence and absorption measurements show the ${}_{}{}^7{}_{}{}^{}F_1^{}{}_{}{}^{}$ levels for ${\mathrm{Eu}}^{3+}$ at 281, 359, and 479 ${\mathrm{cm}}^{-1\mathrm{}}$. The susceptibilities, extrapolated to $T=0\mathrm{}$°K, are fitted with theoretical formulas based on the observed splittings of the ${}_{}{}^7{}_{}{}^{}F_1^{}{}_{}{}^{}$ levels.