Dai Aoki

The novel spin-triplet superconductor candidate UTe₂was discovered only recently at the end of 2018 and already attracted enormous attention. We review key experimental and theoretical progress which has been achieved in different laboratories. UTe₂is a heavy-fermion paramagnet, but following the discovery of superconductivity, it has been expected to be close to a ferromagnetic instability, showing many similarities to the U-based ferromagnetic superconductors, URhGe and U

International audience

We succeeded in growing a new transuranium compound NpPd 5 Al 2 with the tetragonal crystal structure by the Pb-flux method, and measured the electrical resistivity, specific heat, magnetic susceptibility and magnetization. NpPd 5 Al 2 is found to be a paramagnetic heavy-fermion superconductor with strong coupling Δ C /γ T c = 2.33 [ T c =4.9 K and γ= 200 mJ/(K 2 ·mol)]. The upper critical field H c2 at 0 K is large and highly anisotropic: H c2 (0) =37 kOe for H ∥[100] and H c2 (0) =143 kOe for

International audience

We review our recent studies on ferromagnetic superconductors, UGe2, URhGe and UCoGe, together with the ferromagnetic quantum criticality and paramagnetic singularity on the Ising 5f-itinerant system UCoAl. Thanks to the variety of ordered moment in ferromagnetic superconductors from 1.5 muB to 0.05 muB, interesting systematic changes or similarities are clarified. All ferromagnetic superconductors show large upper critical field Hc2, and the field-reentrant (-reinforced) phenomena are observed

We give an overview on experimental studies performed in the last 25 years on heavy-fermion systems in a high magnetic field. The properties of field-induced magnetic transitions in heavy-fermion materials close to a quantum antiferromagnetic-to-paramagnetic instability are presented. Effects of a high magnetic field to the Fermi surface, in particular the splitting of spin-up and spin-down bands, are also considered. Finally, we review on recent advances on the study of non-centrosymmetric comp

We have measured the de Haas-van Alphen effect of PrPb 3 whose antiferroquadrupolar ordering occurs at 0.4 K. Main Fermi surfaces consist of four closed ones, which are almost spherical. These Fermi surfaces are the same as those of a non- f reference compound LaPb 3 in topology, although the cyclotron effective masses are 2 to 6 times larger than those of LaPb 3 . The cyclotron effective masses are temperature-dependent, which starts gradually with decreasing the temperature below 1 K. A metama

Abstract We succeeded in growing high-quality single crystals of UX2 (X = Bi, Sb, As or P) by the self-flux and chemical transport methods and carried out de Haasvan Alphen and Shubnikov-de Haas experiments. We found quasi-two-dimensional Fermi surfaces in these U compounds. Fermi surfaces of UBi2 are found to consist of one spherical Fermi surface and two cylindrical Fermi surfaces. Each Fermi surface in UBi2 changes into two cylindrical surfaces in USb2 and UAs2. This change in the Fermi surfa