Specificities of the behavior of thermoelectric power in CeNi4Ga with an instable valence of Ce
Kazimierz Wielki University, Bydgoszcz, 85-072, Poland
Ivan Franko National University of Lviv, 50 Dragomanova Str., Lviv 79005, Ukraine
WSC of the NAS of Ukraine and MES of Ukraine vul.Mateyka 4, Lviv, 79007, Ukraine
Received February 28, 2019, published online August 27, 2019
The results of the studies in a wide temperature range (4–900 K) of the thermoelectric power for solid solutions RNi4+xGa1–x (R = = Ce, La; 0 ≤ x ≤ 0.5) containing cerium in a state of valence instability are presented. Based on them, an analysis was made of the contribution of the cerium f-states to the thermopower of CeNi4Ga with taking into account the transport properties of the crystal matrix containing the f-electron subsystem. It is shown that the specificities of the temperature behavior of the CeNi4Ga thermopower are caused by a joint manifestation of the effects of the incoherent Kondo scattering of conduction electrons on localized f-centers and scattering on spin fluctuations in the narrow d-band of the nickel sublattice. The anomalously low Kondo contribution to the total thermopower observed in this case is suggested to be associated with the possible weakening of the Kondo- compensation of the magnetic moment of cerium ions due to the structural atomic disorder in its immediate environment.
Key words: rare earth metals and alloys, valence instability, electrical resistivity, thermoelectric power, magnetic susceptibility.