Electronic properties of the Kondo lattice U2Pt2Sn
Abstract
The magnetization M(T,H), specific heat Cp(T,H), 195Pt and 119Sn NMR Knight shifts K(T), electrical resistivity ρ(T), and magnetoresistance MR(T,H) measurements were performed on a polycrystalline sample of antiferromagnetic compound U2Pt2Sn with the Néel temperature TN = 15.7 K. It is found that the Cp(T) and ρ(T) data in the antiferromagnetic state may be interpreted with help of the spin-wave theory with a magnon gap Δ/kB∼6-10 K. Furthermore, analysis of the experimental data allows us to conclude that U2Pt2Sn is a dense Kondo system, in which the exchange interaction, Kondo effect, and crystalline electric field compete with each other on the energy scale TN<TK<ΔCEF. The Kondo-lattice component of the 195Pt and 119Sn NMR Knight shift has been fitted to the two-fluid model for heavy fermions KKL∝(1-T/T*)ln(T*/T) with a characteristic temperature T*∼ 80 K. Electronic properties of heavy-fermion state in U2Pt2Sn are discussed in the context of the Wilson ratio (RW = 2.8), Kadowaki-Woods-Tsujii ratio [A/γ2∼ 2.15 × 10-5μΩcm/(mJ/molUK)2 with N = 2], and an empirical ratio R=T*/TK∼2.
- Publication:
-
Physical Review B
- Pub Date:
- December 2011
- DOI:
- 10.1103/PhysRevB.84.224406
- Bibcode:
- 2011PhRvB..84v4406T
- Keywords:
-
- 71.27.+a;
- 76.60.Cq;
- 75.30.Mb;
- 72.15.Qm;
- Strongly correlated electron systems;
- heavy fermions;
- Chemical and Knight shifts;
- Valence fluctuation Kondo lattice and heavy-fermion phenomena;
- Scattering mechanisms and Kondo effect