Magnetic and Electronic Properties of Ferromagnetic Kondo-Lattice Systems Np2PdGa3

Intermetallic compounds Lu2PdGa3 and Np2PdGa3 have been found to crystallize in an orthorhombic CeCu2-type structure with the Imma space group. The lattice parameters at room temperature are: a = 0.4382(2), b = 0.6870(3) and c = 0.7593(3) nm for Lu2PdGa3 and a = 0.4445(2), b = 0.7089(3) and c = 0.7691(3) nm for Np2PdGa3. The electronic ground-state properties of these compounds were established by magnetic, calorimetric, electrical resistivity, magnetoresistance and Hall coefficient measurements. The experimental data reveal a metallic behavior for Pauli paramagnetic Lu2PdGa3, characterized by Sommerfeld ratio ° = 2.5 mJ/K2mol.Lu and temperature-independent susceptibility Â0 » 1£10¡4 emu/mol. In contrast to the nonmagnetic Lu2PdGa3 reference, Np2PdGa3 behaves as a local-moment ferromagnet with the Curie temperature TC = 62.5(2) K, a large Sommerfeld ratio ° = 120(2) mJ/K2mol.Np and a small Fermi momentum kF = 0.44 ºA¡1. Low-temperature properties of Np2PdGa3 are well interpreted by assuming competition of three different interactions: RKKY (Rudermann-Kittel-Kasuya-Yosida), crystal electric ¯eld and Kondo e®ect, which are represented by respective nergies kBTRKKY , ¢CEF and kBTK. We argue that Np2PdGa3 is a novel Np-based ferromagnetic Kondo-lattice system with TK < TRKKY ¼ ¢CEF .

TRAN V.H.;  GRIVEAU Jean-Christophe;  ELOIRDI Rachel;  MIILLER Wojciech;  COLINEAU Eric; 

2010-10-20

AMER PHYSICAL SOC

JRC59033

1098-0121,   

http://prb.aps.org/abstract/PRB/v82/i9/e094407,    https://publications.jrc.ec.europa.eu/repository/handle/JRC59033,   

10.1103/PhysRevB.82.094407,