Enhanced Electrical Resistivity before Néel Order in the MetalsRCuAs2(R=

Abstract

We report an unusual temperature (T) dependent electrical resistivity (rho) behavior in a class of ternary intermetallic compounds of the type RCuAs2 (R=rare earths). For some rare earths (Sm, Gd, Tb, and Dy) with negligible 4f hybridization, there is a pronounced minimum in rho(T) far above respective Néel temperatures (T(N)). However, for the rare earths which are more prone to exhibit such a rho(T) minimum due to 4f-covalent mixing and the Kondo effect, this minimum is depressed. These findings, difficult to explain within the hitherto-known concepts, present an interesting scenario in magnetism.

Thermodynamic and transport properties of RAgGe (R=Tb–Lu) single crystals

“…It is similar to the ρ(T ) behavior recently found in a different family, RCuAs 2 (for R=Sm, Gd, Tb, Dy) [30]. It has to be seen if this type of behavior indeed requires, as suggested in [30], novel ideas for electrical transport phenomena in the paramagnetic state of relatively simple magnetic metals, but the mere fact that similar, atypical, temperature dependence is observed in resistivity of the members of two unrelated families, RCuAs 2 and RAgGe, in the latter case in single crystals, certainly asks for some theoretical input as well as search for other examples.…”

Electrical resistivity and tunneling anomalies in CeCuAs2

“…Following the observation [1,2] of interesting electrical resistivity (ρ) anomalies for many rare-earths (R) (other than Ce) in the series RCuAs 2 , crystallizing in ZrCuSi 2 -type tetragonal structure, we have taken up the Ce compound, CeCuAs 2 , for investigations. The results of initial investigations have been reported in Ref.…”

Ultrafast resonant magnetic scattering at the soft X-ray free-electron laser FLASH

“…Simultaneously, characteristic upturns in the resistivity curves were observed for some of these compounds below T N which are discussed as possible Kondo systems [1]. For none of the LnMX 2 compounds the magnetic structure has been reported yet.…”

“…Damage thresholds and FEL induced changes in the magnetic properties of the samples as evident in the SAXS signal will be discussed. First experimental results on pump-probe experiment using 120 fs optical pump pulses and 30 fs long FEL probe pulses will be reported [1], [2]. [1] Gutt, C. ;et al Phys Rev B 79, 212406 (2009 The majority of rare earth metal -coinage metal -dipnictides LnMX 2 (Ln = La, Ce -Lu; M = Cu, Ag, Au; X = P, As, Sb) shows antiferromagnetic order at temperatures below T N ≈ 20 K [1,2].…”