Noriko Nakamura

Fermi Surface, Magnetic and Superconducting Properties of LaRhIn5 and CeTIn5 (T: Co, Rh and Ir)

We have studied Fermi surface properties of LaRhIn 5 and CeTIn 5 (T: Co, Rh and Ir) via the de Haas–van Alphen (dHvA) experiment. The Fermi surface of a non-4 f reference compound LaRhIn 5 is quasi...

Quasi-two Dimensional Electronic State of the Antiferromagnet UPtGa5

We have carried out the de Haas–van Alphen (dHvA) experiment to clarify the Fermi surface property of an antiferromagnet UPtGa 5 , and have constructed the magnetic phase diagram from the high-fiel...

Electronic, Magnetic and Superconducting Properties of Quasi-two Dimensional Compounds Ce2RhIn8 and La2RhIn8

We have measured the electrical resistivity, magnetic susceptibility, high-field magnetization, specific heat and de Haas–van Alphen (dHvA) oscillation of Ce 2 RhIn 8 , together with the dHvA oscillation of La 2 RhIn 8 . In La 2 RhIn 8 we detected three kinds of dHvA branches showing cylindrical Fermi surfaces, which are well explained by the result of FLAPW energy band calculations. The corresponding two dHvA branches were detected in Ce 2 RhIn 8 , indicating that the topology of the Fermi surface in Ce 2 RhIn 8 is approximately the same as that of La 2 RhIn 8 . The magnetic susceptibility and magnetization of Ce 2 RhIn 8 were analyzed on the basis of the crystalline electric field scheme of localized-4 f energy levels. Pressure-induced superconductivity was confirmed above 1.2 GPa from the resistivity and ac-susceptibility measurements.

Low Temperature Magnetic Properties of CeTBi2 (T: Ni, Cu and Ag) Single Crystals

A series of the ternary compounds CeTBi 2 (T: Ni, Cu and Ag) have been grown in the single crystalline form by means of the flux method. These compounds crystallize in the tetragonal crystal struct...

Electrical, Thermal and Magnetic Properties of CeNiIn4

We have succeeded in growing a single crystal of CeNiIn 4 with the orthorhombic crystal structure by the In-flux method. CeNiIn 4 is found to order antiferromagnetically below 1.4 K, with a successive change of the magnetic structure below 0.75 K. The magnetic phase diagram was formed by the specific heat and magnetization measurements. The electronic specific heat coefficient is determined as 80 mJ/K 2 ·mol. From these experimental results it is concluded that CeNiIn 4 is a usual 4 f -localized compound.

An unusual hollow cylindrical Fermi surface of a quasi-two-dimensional compound CeAgSb2

Abstract We have carried out the de Haas-van Alphen (dHvA) experiment, together with electrical resistivity, magnetic susceptibility, magnetization and specific heat experiments on a high-quality single-crystal CeAgSb2, which has a small net ferromagnetic moment of 0.4 μB per Ce atom. The bulk magnetic properties are well explained by the crystalline electric field scheme. On the other hand, large dHvA frequencies of 108 Oe, which correspond to cylindrical Fermi surfaces, were detected by the dHvA measurement for the magnetic field along the tetragonal [001] direction, indicating the quasi-two-dimensional electronic structure. The dHvA branches of CeAgSb2 are highly different from those with small dHvA frequencies of 107 Oe for the reference compounds LaAgSb2 and YAgSb2 which exhibit a semimetallic character. The dHvA results have been compared with the results of the energy band calculations. It was concluded that the 4f electron is mainly localized and that the Fermi surface of CeAgSb2 is similar to that of LaAgSb2, but it is slightly enlarged so as to form the large orbits along a hollow cylindrical Fermi surface.

High-Field Magnetization in Pr-based Filled Skutterudite Compounds PrFe4P12 and PrOs4Sb12

High-field magnetization measurements have been performed on the filled skutterudite compounds PrFe 4 P 12 and PrOs 4 Sb 12 with the cubic crystal structure. Magnetization curves along the main symmetry axes of PrFe 4 P 12 show clear anisotropy at high fields. On the basis of this result, we discuss the possible crystalline electric field (CEF) scheme in PrFe 4 P 12 which reproduce the anisotropic feature at high magnetic fields. On the other hand, the magnetization of PrOs 4 Sb 12 for H ∥ at 0.1 K shows weak anomalies at 4.5 and 15 T, which correspond to the phase boundaries of the field-induced antiferroquadrupolar ordering phase. The observed magnetization curve is well explained by the CEF scheme determined by the previous neutron scattering experiments.

Single Crystal Growth and Structural and Magnetic Properties of the Uranium Ternary Intermetallic Compound UCr2Si2

We have grown a single crystal of UCr 2 Si 2 for the first time. UCr 2 Si 2 exhibits a structural transition from the ThCr 2 Si 2 -type ( I 4/ m m m ) to the triclinic structure ( P \bar1) below T a =210 K. The antiferromagnetic structure was determined by means of neutron diffractions, indicating the propagation vector \(Q=[-\frac{1}{2},\frac{1}{2},0]\) and the magnetic moment 0.65µ B /U oriented along the [0,0,1] direction. The high-field magnetization at 4.2 K indicates a metamagnetic transition at 11.4 T, reaching 0.65µ B /U at 14.9 T. The medium size of the electronic specific heat coefficient γ=80 mJ/K 2 mol, the magnetic entropy about half of R ln 2 at T N and a small effective moment 2.45µ B /U indicate that the antiferromagnetic state is due to 5 f -electrons with an itinerant character.