We succeeded in growing single crystals of Mn 2 P and Fe 2 P with the noncentrosymmetric hexagonal structure by the Sn-flux method. Single crystals are in high quality, revealing the residual resistivity ρ 0 = 0.08 µΩ•cm and the residual resistivity ratio RRR(= ρ RT /ρ 0) = 840 in Mn 2 P, and ρ 0 = 0.2 µΩ•cm and RRR = 760 in Fe 2 P. We detected multiply-connected-Fermi surfaces in Mn 2 P from the de Haas-van Alphen experiment.

EuAu 5 with the hexagonal structure is known to be a ferromagnet with the Curie temperature T C = 13 K or 14 K. We succeeded in growing high-quality single crystals by the Bridgman method using the Mo crucible. The residual resistivity ρ 0 and the residual resistivity ratio RRR were ρ 0 = 0.15 µΩ • cm and RRR = 61 for J ∥ [0001]. It was found that the resistivity at room temperature is extremely small as in a simple metal, ρ RT = 9.2 µΩ • cm for J ∥ [0001], which is compared with ρ RT = 32 µΩ • cm for J ∥ [1120]. We observed two magnetic transitions at T C = 15 K and T m = 13.5 K. The latter magnetic transition is of the first-order like one in the specific heat measurement. The magnetization at 2 K saturates at an extremely low field of 2 kOe for H ∥ [0001], with a saturated Eu 2+-moment of 7 µ B /Eu. On the other hand, the hard-axis magnetization for H ∥ [1120] saturates at a high field of 40 kOe. We also clarified the Fermi surface properties by the de Haas-van Alphen effect and energy band calculations, revealing a quasi-one dimensional wavy plate-like Fermi surface. The similar highly anisotropic magnetic properties were observed in EuCu 5 with T C = 84 K.

We grew single crystals of Ti 2 Sn 3 with the orthorhombic crystal structure by the Sn-flux method. Single crystals are in high quality, revealing the residual resistivity ρ 0 = 0.31 µΩ • cm and the residual resistivity ratio RRR = 130. For this compound, we carried out the de Haas-van Alphen (dHvA) experiment. The dHvA frequency, which corresponds to a maximum or minimum cross-sectional area of the Fermi surface, is in the range from 0.3 × 10 7 to 4 × 10 7 Oe, revealing relatively small Fermi surfaces and the cyclotron effective mass is in the range from 0.6 to 4.0 m 0. A relatively large cyclotron mass of 4.0 m 0 claims that conduction electrons are mainly due to the Ti-3d electrons.