Yasunao Miura

Fermi Surface and Superconducting Properties of Non-centrosymmetric LaNiC2

We succeeded in growing single crystals of LaNiC 2 with the non-centrosymmetric orthorhombic structure by the Czochralski method, and measured the electrical resistivity, de Haas–van Alphen effect, and specific heat to clarify the Fermi surface and superconducting properties. This compound has been studied from a viewpoint of the triplet superconducting pairing state. In the present experiment, we observed an ellipsoidal Fermi surface and a multiply-connected-pillar Fermi surface, which are split into two Fermi surfaces, reflecting the antisymmetric spin–orbit interaction based on the non-centrosymmetric crystal structure. The two ellipsoidal Fermi surfaces are split by 230 K, for example. The anisotropy of electrical resistivity and upper critical field H c2 in superconductivity are not large for three principal directions. From the low-temperature specific heat measurement, superconductivity in LaNiC 2 is explained by the framework of the BCS-superconductivity, contrary to the above arguments. The upper...

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 Neel 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 µB/Eu. \(H_{\text{c}}\) is well explained by the magnetic exchange interaction based on a two-sublattice model, using the simple relation Hc = (kB/3µB)(TN-θp), namely, Hc [kOe]=4.9 (TN-θp) [K], where θp is the paramagnetic Curie temperature θp=-36 K. The present anti ferromagnetic state is found to be stable under pressures up to 8 GPa, where the Neel 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 EuBi3 and energy band calculations for the non-\(4f\...

First-Order Antiferromagnetic Transition and Fermi Surfaces in Semimetal EuSn3

We grew high-quality single crystals of the antiferromagnet EuSn3 with the AuCu3-type cubic crystal structure by the Sn self-flux method and measured the electrical resistivity, magnetic susceptibility, high-field magnetization, specific heat, thermal expansion, and de Haas–van Alphen (dHvA) effect, in order to study the magnetic and Fermi surface properties. We observed steplike changes in the electrical resistivity and magnetic susceptibility, and a sharp peak of the specific heat and thermal expansion coefficient at a Neel temperature TN = 36.4 K. The first-order nature of the antiferromagnetic transition was ascertained by the observation of thermal hysteresis as well as of latent heat at TN. The present antiferromagnetic transition is found to be not a typical second-order phase transition but a first-order one. From the results of dHvA experiment, we clarified that the Fermi surface is very similar to that of the divalent compound YbSn3, mainly consisting of a nearly spherical hole Fermi surface and...