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The de Haas–van Alphen effect, which is a powerful method to explore Fermi surface properties, has been observed in cerium, uranium, and nowadays even in neptunium and plutonium compounds. Here, we present the results of several studies concerning the Fermi surface properties of the heavy fermion superconductors UPt 3 and NpPd 5 Al 2 , and of the ferromagnetic pressure-induced superconductor UGe 2 , together with those of some related compounds for which fascinating anisotropic superconductivity, magnetism, and heavy fermion behavior has been observed. [ABSTRACT FROM AUTHOR]

Fermi surface properties in rare earth (R) and actinide (An) compounds of RX3 (X: Al, Ga, In, Si, Ge, Sn, Pb), AnX3, RTIn5 (T: transition metal), and AnTGa5 are clarified as a function of the number of valence electrons. The electronic state can be changed by applying pressure and magnetic field. A change of Fermi surface properties associated with the metamagnetic behavior and the quantum critical point is also clarified precisely, together with the split Fermi surfaces in the non-centrosymmetric crystal structure, and the de Haas-van Alphen oscillations in the superconducting mixed state. In the quantum critical point region, the conduction electrons, or quasi-particles, are of an f-electron character, with heavy effective masses of 10-100 m0 (m0 is the rest mass of an electron) and condense into the unconventional (anisotropic) superconducting state. [ABSTRACT FROM AUTHOR]

Abstract: We have investigated a change of the electronic state in via de Haas–van Alphen (dHvA) experiments under pressure up to 2.72GPa for the magnetic field along . A main Fermi surface with the dHvA frequency Oe and a large cyclotron mass was observed at 2.72GPa in the vicinity of the critical pressure where the Néel temperature is suppressed to zero. [Copyright &y& Elsevier]

We present the quasi-two-dimensional Fermi surface studies in RTIn5 (R: rare earth, T: Co, Rh and Ir), together with UTGa5. The present quasi-two dimensionality is closely related to the unique crystal structure elongated along the [0 0 1] direction, which brings about a flat Brillouin zone and produces cylindrical but highly corrugated Fermi surfaces along [0 0 1]. [Copyright &y& Elsevier]

Abstract: The topology of the Fermi surface in CePt3Si is most likely similar to that in LaPt3Si. In fact, one small Fermi surface in CePt3Si is the same as that in LaPt3Si, where the main Fermi surface in LaPt3Si consists of three-dimensional multiply-connected Fermi surfaces. With increasing pressure, the topology of the Fermi surface in CePt3Si is approximately unchanged but the cyclotron effective mass is found to be reduced, together with a steep decrease of the Néel temperature and superconducting transition temperature. These results indicate that the heavy fermion state in CePt3Si, which is closely correlated with superconductivity, is stable at ambient pressure. [Copyright &y& Elsevier]

Abstract: We measured the magnetic susceptibility and magnetization of an antiferromagnet Ce3Sn7 with the orthorhombic crystal structure. The experimental data are found to be well explained on the basis of the crystalline electric field (CEF) 4f-scheme under the assumption that two Ce atoms in the 2(a) site possess a magnetic moment of and one Ce atom in the 4(i) site possesses no magnetic moment as in a valence fluctuating compound CeSn3, which was previously proposed by Bonnet et al. Furthermore, we carried out the de Haas–van Alphen experiment. The detected Fermi surfaces are many in number but are extremely small in volume, indicating that Ce3Sn7 is a semimetal. [Copyright &y& Elsevier]

In order to investigate the magnetic structure and Fermi surface properties of UNiGa5, we have performed elastic neutron scattering and de Haas-van Alphen(dHvA) experiments. In the neutron scattering experiment using a single crystalline sample, we determined the antiferromagnetic propagation vector Q=(1/2,1/2,1/2) in UNiGa5. In the dHvA experiment, we observed four branches. Two branches indicate cylindrical Fermi surface and the other two branches correspond to ellipsoidal ones. The cyclotron mass was not large, ranging from 1.3 to 3.1m0. [Copyright &y& Elsevier]

The angular dependence of de Haas–van Alphen effect has been measured to reveal the electronic structure of filled skutterudite PrRu4Sb12. The angular dependence of de Haas–van Alphen frequency of PrRu4Sb12 is in good agreement with that of LaRu4Sb12. Compared with PrFe4P12, no anomalous enhancement of cyclotron effective mass has been observed in this system. This change of electronic structure is attributed to the difference in the c−f hybridization strength, which is expected from the large difference in the lattice parameters. [Copyright &y& Elsevier]