Heavy fermion behavior in CePtSi and CeRuSi

Abstract

We present results of specific heat, electrical resistance, and magnetic susceptibility measurements on the heavy fermion system CePtSi and compare it to CeRuSi. Both compounds show a low-temperature maximum in cp/T, usually associated with the formation of a coherent heavy fermion ground state. An additional feature in cp/T is observed for CePtSi and is attributed to cooperative magnetism, an interpretation confirmed by magnetic measurements. A comparison with other heavy fermion systems, especially stoichiometric and nonstoichiometric CeCu2Si2, is performed.

Heavy-electrons: New materials

“…The tetragonal compound CePtSi has been found to show both some kind of magnetic order near 3 K and a y below 1 K of 840 mJ/mol Ce K 2 [12]. Shelton et al [13] have also worked on this material• Sereni et al [14] have found the extremely large y = 3.9 m J/tool Ce K 2 in the cubic CePd3B.…”

Hydrogenation inducing antiferromagnetism in the heavy-fermion ternary silicide CeRuSi

“…In the present paper, we will discuss the effect of hydrogenation on the ternary silicide CeRuSi, which crystallizes in the tetragonal CeFeSi-type structure and is considered as a nonmagnetic heavy-fermion system. 13 Its investigation by specific heat ͑C p ͒ measurements reveals a shallow maximum at 0.5 K and an electronic coefficient ␥ = C p / T = 220 mJ/ mol K 2 , which is indicative of a moderate heavy-fermion character. This low-temperature behavior can be associated with the formation of a coherent heavyfermion ground state, and the analysis of the specific heat measurements within the one-impurity Kondo model has suggested a large Kondo temperature of the order of 25 K. 13 The absence of magnetic ordering for CeRuSi was confirmed above 4.2 K by neutron powder diffraction.…”

“…13 Its investigation by specific heat ͑C p ͒ measurements reveals a shallow maximum at 0.5 K and an electronic coefficient ␥ = C p / T = 220 mJ/ mol K 2 , which is indicative of a moderate heavy-fermion character. This low-temperature behavior can be associated with the formation of a coherent heavyfermion ground state, and the analysis of the specific heat measurements within the one-impurity Kondo model has suggested a large Kondo temperature of the order of 25 K. 13 The absence of magnetic ordering for CeRuSi was confirmed above 4.2 K by neutron powder diffraction. 14 Finally, x-ray absorption spectroscopy at the Ce L III edge gives a measured valence of 3.14 for cerium in this ternary silicide.…”

Investigation of phases obtained from the Ce20Ru60Si20 composition

“…The non-centrosymmetric crystal structure of the CePt 3 B-type is adopted also in the CePt 3 Si case, although the ratio between the B and Si atomic radii R is considerably large R B /R Si = 0.74. On the other hand, the atomic radii of Ru and Pt are very close (R Ru /R Pt = 0.96) and there are many examples of formation of isostructural Ru-and Pt-containing analogous compounds in literature [2,22,23]. However, it does not hold for CeT 3 Si with Pt and Ru [24].…”