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J-C. Griveau

Publications and source records attributed to J-C. Griveau.

2 recordsLinked to original sources

On the magnetic and electronic properties of NpPdSn

We have studied NpPdSn by means of the heat capacity, electrical resistivity, Seebeck and Hall effect, $^{237}$Np Mössbauer spectroscopy, and neutron diffraction measurements in the temperature range 2-300 K and under magnetic fields up to 14 T. NpPdSn orders antiferromagnetically below the Néel temperature $T_N$ = 19 K and shows localized magnetism of Np$^{3+}$ ion with a a doubly degenerate ground state. In the magnetic state the electrical resistivity and heat capacity are characterized by electron-magnon scattering with spin-waves spectrum typical of anisotropic antiferromagnets. An enhanced Sommerfeld coefficient and typical behavior of magnetorestistivity, Seebeck and Hall coefficients are all characteristic of systems with strong electronic correlations. The low temperature antiferromagnetic state of NpPdSn is verified by neutron diffraction and $^{237}$Np Mössbauer spectroscopy and possible magnetic structures are discussed.

cond-mat.str-el

Thermoelectric power as a probe of density of states in correlated actinide materials: the case of PuCoGa$_{5}$ superconductor

We present measurements of the thermoelectric power of the plutonium-based unconventional superconductor PuCoGa$_{5}$. The data is interpreted within a phenomenological model for the quasiparticle density of states of intermediate valence systems and the results are compared with results obtained from photoemission spectroscopy. The results are consistent with intermediate valence nature of 5$f$-electrons, furthermore, we propose that measurements of the Seebeck coefficient can be used as a probe of density of states in this material, thereby providing a link between transport measurements and photoemission in strongly correlated materials. We discuss these results and their implications for the electronic structure determination of other strongly correlated systems, especially actinide materials.

cond-mat.str-el