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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...

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\...

We succeeded in growing a high-quality single crystal of an antiferromagnet UPtGa 5 by the self-flux method, and measured the magnetic susceptibility, electrical resistivity, specific heat and de H...

EuNi2P2 is known as a heavy fermion compound with an electronic specific heat coefficient γ=100 mJ/(K2 \(\cdot\)mol). We grew single crystals and studied their electronic and magnetic properties by measuring the electrical resistivity, magnetic susceptibility, high-field magnetization, specific heat, and thermal expansion. The present heavy fermion state is clarified to be based on the Kondo effect as in CeRu2Si2, revealing an intensive shrinkage of the volume below about 100 K in the temperature dependence of thermal expansion. The temperature dependences of the \(4f\)-electron contribution to the volume thermal expansion Δ V/V)4f and the average Eu valence are found to show good scaling in EuNi2P2.

We measured the electrical resistivity, magnetic susceptibility, magnetization, and specific heat of the quasicrystal approximants RCd 6 (R: rare earth, Y–Lu) with a body-centered cubic (bcc) crystal structure. Single crystals were grown by the Cd-self flux method and annealing method. We confirmed that the structural order–disorder transition is realized at about 160 K when the lattice constant a is larger than 15.481 A in YCd 6 , namely, for R = Pr, Nd, Sm, Gd, Tb, Dy, and Yb. At lower temperatures, RCd 6 compounds, except non-4 f reference compounds YCd 6 and LuCd 6 , and a divalent compound YbCd 6 , are found to order antiferromagnetically. We clarified that the structural order–disorder transition has a great influence on the magnetic ordering and transport properties. The Neel temperature of RCd 6 (R: Nd, Sm, Tb, and Dy) with the structural order–disorder transition is appreciably higher than the de Gennes scaling normalized by the Neel temperature of GdCd 6 , while the the Neel temperature of RCd 6...

We measured the electrical resistivity of a prototype heavy fermion antiferromagnet CeAl 3 in the temperature range from 0.1 K to room temperature under various magnetic fields and pressures. The heavy fermion state at ambient pressure is drastically destroyed under a small pressure and magnetic field.

Neel temperatures in RIr 2 Zn 20 (R: rare earth) with the cubic caged structure are found to be very low, which are below T N =5.0 K for GdIr 2 Zn 20 . This is mainly due to the long R–R distance and R atoms are spherically surrounded by Zn atoms. The corresponding crystalline electric field (CEF) splitting energies are also small, being below 100 K.

We measured the electrical resistivity, magnetic susceptibility, and specific heat in quasicrystal approximants RCd 6 . It was confirmed that the structural order–disorder transition of a tetrahedron with 4Cd atoms occurs at about 160 K when the lattice constant a is longer than a = 15.481 A in YCd 6 , namely for RCd 6 (R: Y, Pr, Nd, Sm, Gd, Tb, Dy, and Yb ). The structural transition is found to have a great influence on the low-temperature electrical resistivity.

The enhancement ofTc in Pb-Bi-Sn and Pb-Bi-In system alloy filaments produced by glass-coated melt spinning was investigated as a means of producing a new type of superconducting filament with highTc. Long filaments of Pb-Bi-Sn alloy withTc higher than 10 K and Pb-Bi-In alloy withTc higher than 9 K were obtained from the molten state at a temperature of 1500 K with a winding speed of 2.63 m sec−1. For example, a Pb45Bi35Sn20 filament withTc of 10.1 K was 15 μm in diameter and polycrystalline with a grain size of 100 nm. The structure of the filament was a mixture of ɛ, tin and bismuth phases and a metastable phase of mixed structure of bismuth and supersaturated solid solution of tin in ɛ-phase was detected. TheTc of the filament decreased on heat treatment. A metastable phase of mixed structure of bismuth and ɛ-phase was also detected for a Pb45Bi45In10 filament withTc of 9.3 K. As the metastable phase for the Pb-Bi-In filament was more unstable than that for the Pb-Bi-Sn filament, theTc of the filament was drastically decreased by heat treatment. The metastable phase was considered to play an important role in the enhancement ofTc for Pb-Bi-Sn and Pb-Bi-In alloy filaments.