Fermi Surface and Magnetic Properties of Antiferromagnet EuBi

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EuBi<inf>3</inf>with the AuCu<inf>3</inf>-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<inf>3</inf>and energy band calculations for the non-4f reference compound SrBi<inf>3</inf>, the Fermi surface is found to consist of three types of nearly spherical Fermi surfaces.
2013-12-15