One impurity effect of Tm in YSe. Kondo effect and Van Vleck behavior

Abstract

Des mesures d'aimantation et de résistivité sur le système dilué Tm^Yi^Se montrent à la fois des comportements de type Tm 2+ et Tm 3+ . Cependant, comme les résultats sont presque linéaires en concentration, ils paraissent refléter les propriétés de chaque site de thulium.Abstract. -Low temperature magnetization and resistivity measurements in the dilute Tm^Y! _JSe system show both Tm 2+ and Tm 3+ like behavior. However, since the results are nearly linear with concentration, they apparently reflect the properties of each thulium site.

Valence instabilities of Tm in its compounds and solid solutions

“…The slope of the log T region is roughly proportional to the Tm ion concentration consistent with the single impurity behavior based on magnetic properties. A detailed discussion of the Kondo effect in the yttrium system is given by Berger et al [20]. The Kondo effect is also observed in the Tm,~,oLa,~,oSe sample.…”

“…The TmSe value shown corresponds to a nearly stoich~ometric sample. The lines drawn to 5.95 8, and 5.64 A correspond to the values expected for purely TmZ + and Tm3 + , respectively.Berger et al on dilute Tm in YSe[20]. They find both Curie and Van Vleck behavior in the low temperature susceptibility and magnetization, proportional to Tm concentration.The reciprocal susceptibility vs. temperature of the Tmo,,oYo~,,Se sample is shown infigure 6.…”

The Ground State of Dilute Tm Systems is Degenerate

“…[24], this fact is difficult to reconcile with the experiments. It has been argued [23] that the magnetic behaviour of Tm compounds is due to magnetic interactions between Tm ions, but then, the divergent magnetic susceptibility [12] and neutron scattering experiments [13,14] of Tm impurities at low temperatures remain unexplained. On the other hand, all the above-mentioned studies [22-241 neglected one of both hybridization channels V' ( j = Z f 1/2, see eq.…”