Anomalous ferromagnetism and non-Fermi-liquid behavior in the Kondo lattice CeRuSi2

Abstract

The structural, electronic and magnetic properties of the Kondo-lattice system CeRuSi2 are experimentally investigated and analyzed in the series of other ternary cerium compounds. This system is shown to be an excellent model system demonstrating coexistence of the Kondo effect and anomalous ferromagnetism with a small magnetic moment which is confirmed by magnetic and µSR measurements. Data on specific heat, resistivity, heat conductivity and Seebeck coefficient are presented. Being deduced from the resistivity and specific heat data, a non-Fermi-liquid behavior is observed at low temperatures, which is unusual for a ferromagnetic Kondo system. A comparison with other magnetic Kondo lattices is performed.

Ferromagnetism and transport properties of the Kondo system Ce4Sb1.5Ge1.5

“…The small value of saturation moment obtained (about 0.1μ B , Fig.2) is also typical for the dense Kondo systems because of the Kondo screening. A similar situation takes place, e.g., in the compound CeRuSi 2 [2]. The T 4/3 -interpolation characteristic for weak itinerant ferromagnetism with strong non-spinwave fluctuations turns out to fit our data somewhat better than the T 3/2 -interpolation (spin-wave theory for localized systems).…”

“…In particular, they can demonstrate anomalous magnetic ordering (including small magnetic moments), which is accompanied by anomalies of electronic characteristics [1,2]. Besides that, some systems have promising thermoelectric properties, i.e.…”

Magnetotransport and magnetic properties of amorphous $$\mathrm{NdNi}_5$$ thin films

“…The presence of these two different temperature regimes is also observed when measuring the temperature dependence of the magnetic moment of these samples which indicate a K in the 125-nm-thick sample. Interestingly, this study reveals the coexistence of Kondo effect and ferromagnetic ordering as already reported in different classes of crystalline materials, such as for instance ternary intermetallic Ce- and Np-based compounds 37 , 48 , 49 . Although unusual, this occurrence is not unexpected in amorphous ferromagnets, where structural and compositional disorder may produce a distribution of internal effective exchange field 50 , 51 , which could result in the increase in observed in our amorphous films with respect to crystalline specimens 13 .…”

Monte Carlo study of the ordering in a strongly frustrated liquid crystal

“…However, the entropy in both the high and low temperature limits differs between the spin and the chain models: S spin = k B log e 7 compared with S chain = k B log e 8 as T → ∞ and S spin > k B 3 (1.0029)log e 7 and S chain = 0 as T → 0. [15]. This mapping was not exact because the mapping did not allow for the different multiplicities for different occupations of the chains within a hexagon and also because of the necessity to have Kawasaki dynamics [16].…”