dHvA Branches Research Articles

Fermi Surface and Magnetic Properties of the Antiferromagnet UIn3

We succeeded in growing a high-quality single crystal of UIn 3 by the self-flux method and measured the electrical resistivity, magnetic susceptibility, magnetization, specific heat and de Haas-van Alphen (dHvA) oscillation. We confirmed the Néel temperature at T N =88 K from both the electrical resistivity and magnetic susceptibility measurements. We observed many dHvA branches. The Fermi surfaces are found to consist of closed Fermi surfaces and a multiply-connected Fermi surface. The cyclotron mass is relatively large, ranging from 9.8 to 33 m 0 .

Magnetic and Fermi Surface Properties of UFeGa5

We succeeded in growing a high-quality single crystal of UFeGa 5 by the self-flux method and measured the electrical resistivity, magnetic susceptibility, magnetization and de Haas-van Alphen (dHvA) oscillation. Many dHvA branches were observed, ranging from 5.4×10 5 to 1.4×10 8 Oe. These branches are in good agreement with theoretical ones based on 5 f -itinerant RLAPW band calculations. The cyclotron mass is relatively large, ranging from 2.4 to 9.9 m 0 .

De Haas–van Alphen effect and transverse magnetoresistance in FeP

The 3d transition metal monopnictides show various interesting electric and magnetic properties. In this study, we have measured the dHvA effect and the transverse magnetoresistance in FeP which has the MnP-type structure and is antiferromagnetic below 125 K with the double helical spin structure. Ten dHvA branches were observed in the (0 0 1) and (1 0 0) planes and their cyclotron mass ratios at the [0 1 0] direction are 0.6–2.2.

Fermi Surface Properties of USi3

We succeeded in growing a single crystal of USi 3 with the cubic crystal structure and measured the transverse magnetoresistance and de Haas-van Alphen(dHvA) oscillation. Fifteen dHvA branches were observed, ranging from 7.37×10 6 to 2.33×10 8 Oe. These branches are in good agreement with theoretical ones based on 5 f -itinerant FLAPW band calculations. Cyclotron masses, which are in the range from 0.39 to 4.17 m 0 , are approximately the same as the corresponding band masses. These results indicate that the itinerant 5 f -electrons form wide bands. The magnetoresistance results confirmed the existence of open orbits, which can be well explained by the band 10-electron Fermi surface.

De Haas–van Alphen effect and magnetoresistance in YbBi 2

We have measured the de Haas–van Alphen (dHvA) effect and the magnetoresistance in orthorhombic YbBi 2. The eight dHvA branches α, β, γ, δ, ε, ζ, η, and θ were observed in the frequency range of 40–4000 T. The cyclotron masses range from 0.07 m 0 to 1.4 m 0. The lowest-frequency branch α originates from a small cylindrical Fermi surface elongated the b-axis. The branch β corresponds to a nearly spherical Fermi surface with the frequency about 1700 T. The branches γ, δ, ε, and ζ with the frequencies 2000–4000 T are in limited field angle region near the b-axis. The results of the magnetoresistance are explained by above Fermi surface features with the open orbit along the b-axis.

De Haas–van Alphen effect in CeNi under pressure

An intermediate valence compound CeNi exhibits a phase transition under pressure, which is associated with the γ–α transition in Ce. To clarify a change of the electronic state under pressure, we measured the de Haas–van Alphen (dHvA) effect under pressure up to 6 kbar using a Cu–Be pressure cell. The dHvA branches are still observed after the phase transition. The topology of the Fermi surface is therefore unchanged. The cyclotron effective mass is, however, reduced from 11 to 3.2 m 0 for branch ε and from 5.4 to 1.2 m 0 for branch σ when the pressure is changed from 1 bar to 3.7 kbar.

Single-crystal growth and de Haas–van Alphen effect of YbAl 3

We succeeded in observing the de Haas–van Alphen (dHvA) oscillation of YbAl 3. The single crystals were grown by the self-flux method. The residual resistivity and residual resistivity ratio were 0.5 μΩ cm and 60, respectively. Three fundamental dHvA branches were detected for the magnetic field along the 〈1 0 0〉 direction. Their cyclotron masses were in the range from 8.1 to 22 m 0, reflecting a relatively large electronic specific heat coefficient γ=58 mJ/K 2 mol.

Fermi surface of UB 4 studied by the de Haas–van Alphen oscillation and magnetoresistance experiments

We grew a high-quality single crystal of UB 4 with the tetragonal structure and carried out the magnetoresistance and de Haas–van Alphen (dHvA) experiments. The magnetoresistance data indicate that UB 4 is a compensated metal with equal numbers of electrons and holes, and has open orbits along the [1 0 0] and [0 1 0] directions. We detected about 11 dHvA branches. The cyclotron masses are moderately heavy, ranging from 3.0 to 14.1 m 0, reflecting the electronic specific heat coefficient of 24.9 mJ/K 2 mol.

Heavy Fermions in YbAl3Studied by the de Haas-van Alphen Effect

We carried out the de Haas-van Alphen (dHvA) experiment in YbAl 3 with the cubic crystal structure. One of the six dHvA branches, named β with a dHvA frequency of 4.5×10 7 Oe, is nearly spherical in topology and has a large cyclotron mass of 23.9 m 0 . The other branches were observed only in small angular regions centered at symmetrical directions. Their cyclotron masses are in the range from 13.5 to 17.4 m 0 . The topology of the Fermi surface cannot be explained by the conventional band model because the fully occupied 4 f -levels in YbAl 3 are below the Fermi level. A small alteration so as to shift upwards the 4 f -levels is necessary to fit to the experimental dHvA data. These give a direct evidence that the 4 f -electrons form heavy fermions at low temperatures, which is most likely related to the many-body Kondo effect.

Fermi Surface and de Haas-van Alphen Oscillation in both the Normal and Superconducting Mixed States of UPd2Al3

The dHvA oscillation was observed clearly in both the normal and superconducting mixed states for UPd 2 Al 3 with the hexagonal structure. Eight kinds of dHvA branches were detected, which are well explained by the results of band calculations based on a fully-relativistic spin-polarized LAPW method. An inner orbit of a band 41-hole Fermi surface, named ζ, has the largest dHvA frequency of 9.45×10 7 Oe and cyclotron mass of 65 m 0 , reflecting a large electronic specific heat coefficient of 145 mJ/K 2 ·mol. Branch α of a band 40-hole Fermi surface was observed in both the normal and superconducting mixed states, where the dHvA frequency does not change in magnitude between the normal and mixed states. The cyclotron effective mass of branch α is, however, found to be reduced and the corresponding Dingle temperature or scattering rate of the conduction electron increases with decreasing the field in the mixed state. An anisotropic energy gap with a line node for UPd 2 Al 3 is discussed from the angular depe...

De Haas-van Alphen Effect and RLAPW-Energy Band Calculations in CeNi

We have carried out the de Haas-van Alphen (dHvA) experiments in a valence fluctuating compound CeNi. Forty seven dHvA branches are observed experimentally, which are mainly centered at the symmetrical axes. Most of the dHvA branches are approximately explained by the 4 f -itinerant band model. The cyclotron mass is in the range from 3.0 to 27 m 0 . Branch α, which has the largest cross-sectional area of the Fermi surface in the detected branches along the a -axis, has the cyclotron mass of 27 m 0 . This mass is five times larger than the corresponding band mass of 5.45 m 0 .

Magnetoresistance and de Haas-van Alphen Effect in UB4

We grew a single crystal of UB 4 with the tetragonal structure and carried out the magnetoresistance and de Haas-van Alphen (dHvA) experiments. The magnetoresistance data indicate that UB 4 , which is a compensated metal with equal carrier numbers of electrons and holes, most likely has open orbits along the [100] and [010] directions. We detected about eleven dHvA branches. The cyclotron masses are moderately heavy, ranging from 3.0 to 14.1 m 0 , reflecting the electronic specific heat coefficient of 24.9 mJ/K 2 ·mol.

Crystal Growth and Cylindrical Fermi Surfaces of USb2

We have grown high-quality single crystals of tetragonal USb 2 using a flux method. We have detected five branches in de Haas-van Alphen (dHvA) experiments. Frequencies of all dHvA branches follow ...

De Haas–van Alphen Effect and Electronic Band Structure of NiAs

We have measured the de Haas–van Alphen effect at 0.55 K in the field up to 9.5 T for the single crystal of Pauli paramagnetic NiAs. Six dHvA branches have been observed and they show complicated behavior as a function of the field direction which is applied in the symmetry planes (11\bar20), (10\bar10) and (0001). The corresponding cyclotron masses have been also determined from the temperature dependence of the dHvA amplitude. To discuss the experimental results we have performed the electronic band calculation of NiAs for the non-magnetic state by using the full potential LAPW method. The total energy calculated as a function of the lattice parameter a , keeping the ratio c / a as the observed value, becomes minimum at 3.60 A, which agrees very well with the observed one. The Fermi surface is found to consist of two kinds of hole surface around the ΓA axis and one electron surface with six fold symmetry. For each Fermi surface we have calculated dHvA oscillation frequencies and succeeded to explain the...

Fermi surfaces of RPb 3

We have observed the de Haas–van Alphen (dHvA) oscillations in SmPb 3, GdPb 3, EuPb 3 and YbPb 3. Detected dHvA branches are discussed on the basis of the result of the FLAPW band calculation.

Fermi surface of UB 2 studied by the de Haas–van Alphen oscillation

We observed the de Haas–van Alphen (dHvA) oscillation of UB 2 with a hexagonal structure. All of the detected dHvA branches, which are about seven in number, are detected in the limited angle regions. The cyclotron masses are moderately heavy, ranging from 1.2 to 7.7 m 0. These features of the Fermi surface are well explained by the 5f-itinerant band theory.

De Haas-van Alphen Effect and Energy Band Structure in UB2

We grew a single crystal of UB 2 with the hexagonal structure and observed the de Haas-van Alphen (dHvA) oscillation. All of the dHvA branches, which are about seven in number, are detected in the limited angle regions. They are well explained by the 5 f -itinerant relativistic band theory with an exchange and correlation potential in a local density approximation. Namely, UB 2 is a compensated metal with an equal number of electron and hole. The Fermi surface consists of two closed but corrugated Fermi surfaces. The cyclotron masses are moderately heavy, ranging from 1.2 to 7.7 m 0 .

Thermal Expansion and de Haas-van Alphen Effect of CeRh2Si2

We have grown single crystals of CeRh 2 Si 2 and LaRh 2 Si 2 , and measured the temperature dependence of the thermal expansion coefficient. The magnetic component of the thermal coefficient in CeRh 2 Si 2 has been analyzed on the basis of the crystalline electric field. We have also succeeded in observing the de Haas-van Alphen (dHvA) effect of CeRh 2 Si 2 . The detected dHvA branches are small in cross-section and are observed in a narrow angle region centered at the symmetrical axis, reflecting the multiply-connected Fermi surface.

Magnetic and Electrical Properties of GdCu2

We measured the electrical resistvity, specific heat and de Haas-van Alphen (dHvA) oscillation of an antiferromagnetic compound GdCu 2 . The magnetic entropy, which was obtained from the specific heat, reaches R ln 8 above 47 K, which is close to the Neel temperature of 40 K. The dHvA branches both in the antiferromagnetic state and the field-induced ferromagnetic state are highly different from those of a non-magnetic reference compound YCu 2 or PrCu 2 . The Fermi surface in GdCu 2 is most likely altered by the magnetic state.

De Haas-van Alphen Effect Study of CeRh2Si2

The de Haas-van Alphen (dHvA) effects have been studied in an antiferromagnetic heavy Fermion compound CeRh 2 Si 2 with fields in the high symmetry planes of (001), (1\=10) and (010). More than twenty separate dHvA branches have been observed ranging from 33 T to 9170 T; most of the branches are observed in limited regions of the field directions. The largest cyclotron mass obtained is 4.4 m 0 , which is rather small compared to the estimate from the Sommerfeld coefficient. This implies that heavy Fermi surfaces remain uncovered.