Ferromagnetic behavior of the Kondo lattice compound Np2PtGa3

Article

关键词: MAGNETIC-SUSCEPTIBILITY;    TRANSPORT-PROPERTIES;    HEAT;    CRYSTALLINE;    NPO2;   

DOI  :  10.1103/PhysRevB.89.054424

来源: SCIE

【 摘 要 】

Here we report on a study of the ternary Np2PtGa3 compound. The x-ray-powder diffraction analysis reveals that the compound crystallizes in the orthorhombic CeCu2-type crystal structure (space group Imma) with lattice parameters a = 0.4409(2) nm, b = 0.7077(3) nm, and c = 0.7683(3) nm at room temperature. The measurements of dc magnetization, specific heat, and electron transport properties in the temperature range 1.7-300 K and in magnetic fields up to 9 T imply that this intermetallic compound belongs to a class of ferromagnetic Kondo systems. The Curie temperature of T-C similar to 26 K is determined from the magnetization and specific-heat data. An enhanced coefficient of the electronic specific heat gamma = 180 mJ/(mol at. Np K-2) and a -lnT dependence of the electrical resistivity indicate the presence of a Kondo effect, which can be described in terms of the S = 1 underscreened Kondo-lattice model. The estimated Kondo temperature T-K similar to 24 K, Hall mobility of similar to 16.8 cm(2)/V s, and effective mass of similar to 83m(e) are consistent with an assumption that the heavy-fermion state develops in Np2PtGa3 at low temperatures. We compare the observed properties of Np2PtGa3 to that found in Np2PdGa3 and discuss their difference in regard to change in the exchange interaction between the conduction and localized 5f electrons. We have used the Fermi wave vector k(F) to evaluate the Rudermann-Kittel-Kasuya-Yosida (RKKY) exchange. Based on experimental data of the (U, Np)(2)(Pd, Pt)Ga-3 compounds we suggest that the evolution of the magnetic ground states in these actinide compounds can be explained within the RKKY formalism.

【 授权许可】

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