Fermi Surface and Magnetic Properties of Antiferromagnet EuBi3

EuBi 3 with the AuCu 3 -type cubic structure is known to be a Eu-divalent antiferromagnet with the Néel temperature $T_{\text{N}}\simeq 7.5$ K. We succeeded in growing a high-quality single crystal by the Bi self-flux method. The magnetization at 1.3 K for the magnetic field along the $\langle 100\rangle$ direction increases linearly as a function of magnetic field, and saturates at a critical field $H_{\text{c}}=225$ kOe, reaching a saturated magnetic moment of 7 $\mu_{\text{B}}$/Eu. $H_{\text{c}}$ is well explained by the magnetic exchange interaction based on a two-sublattice model, using the simple relation $H_{\text{c}} = (k_{\text{B}}/3\mu_{\text{B}})(T_{\text{N}}-\theta_{\text{p}})$, namely, $H_{\text{c}}\ [\text{kOe}]=4.9\ (T_{\text{N}}-\theta_{\text{p}})\ [\text{K}]$, where $\theta_{\text{p}}$ is the paramagnetic Curie temperature $\theta_{\text{p}}=-36$ K. The present anti ferromagnetic state is found to be stable under pressures up to 8 GPa, where the Néel temperature increases with increasing pressure, being $T_{\text{N}}=16.5$ K at 8 GPa. From the results of de Haas--van Alphen experiments on EuBi 3 and energy band calculations for the non-$4f$ reference compound SrBi 3 , the Fermi surface is found to consist of three types of nearly spherical Fermi surfaces.