Fermi surface and magnetic properties of antiferromagnet EuBi₃

EuBi3 with the AuCu₃-type cubic structure is known to be a Eu-divalent antiferromagnet with the Néel temperature T_N ∼ 7:5 K. We succeeded in growing a high-quality single crystal by the Bi self-flux method. The magnetization at 1.3K for the magnetic field along the h100i direction increases linearly as a function of magnetic field, and saturates at a critical field H_c = 225 kOe, reaching a saturated magnetic moment of 7μB/Eu. H_c is well explained by the magnetic exchange interaction based on a two-sublattice model, using the simple relation H_c = (kB/3μ_B)(T_N- θ_p) namely, H_c [kOe= 4:9 (T_N - θ_p) [K], where θ_p is the paramagnetic Curie temperature θ_p = -36 K. The present antiferromagnetic state is found to be stable under pressures up to 8 GPa, where the Néel temperature increases with increasing pressure, being T_N = 16:5K at 8 GPa. From the results of de Haas-van Alphen experiments on EuBiT₃ and energy band calculations for the non-4f reference compound SrBi₃, the Fermi surface is found to consist of three types of nearly spherical Fermi surfaces.