Unconventional superconducting characteristics of heavy fermion

actinide superconductors

Yoshinori Haga

Advanced Science Research Center, Japan Atomic Energy Agency, Japan


    The physical properties of actinide compounds are characterized by their 5f electrons. Compared to 4f electrons in rare earth, 5f electrons are delocalized and participate both in magnetic and transport properties. On the other hand, because of their radioactivity, the experimental studies are limited. Among the actinides, therefore, only uranium was mainly studied.

    Recently, superconductors with transuranium elements, Np and Pu, have been discovered. PuCoGa5 [1] and PuRhGa5 [2] crystallized in the tetragonal HoCoGa5 structure and show superconductivity at fairly high-temperatures at 18 and 9 K, respectively. On the other hand NpPd5Al2 is the first neptunium-based heavy fermion superconductor. These compounds show a higher superconducting transition temperature compared to other heavy fermion Ce- or U- based superconductors. We will review the physical properties of these compound in comparison with other heavy fermion superconductors.



[1] J. L. Sarrao, et al., Nature (London) 420 (2002) 297.

[2] Wastin, J. Phys.: Condens. Matter 15 (2003) S2279.

[3] D. Aoki, et al., J. Phys. Soc. Jpn. 76 (2007) 063701.

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