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. © 1967 The American Physical Society.