Magnetocrystalline Anisotropy of Single-Crystal Europium Oxide

The first-order cubic anisotropy constant K₁ in EuO single crystal was measured as a function of temperature and applied field by the static torque method. The value at T=0^∘K is K₁(0)=-(4.36±0.1)×10⁵ erg/cm³. The variation of K₁ with T and H is uniquely described by the behavior of the measured magnetic moment σ(H, T). The observed relationship between K₁(H, T)K₁(0, 0) and σ(H, T)σ(0, 0) is explained by a theory of single-ion interaction with the cubic crystal potential. The cubic crystal-field splitting parameter b₄=(21.2±0.5)×10^-4 cm^-1/ion obtained from K₁(0) is compared with results for Eu⁺⁺ ions in various other materials.