CeNiAsO: an antiferromagnetic dense Kondo lattice

Abstract

Abstract. A cerium containing pnictide, CeNiAsO, crystallized in the ZrCuSiAs type structure, has been investigated by measuring transport and magnetic properties, as well as specific heat. We found that CeNiAsO is an antiferromagnetic dense Kondo lattice metallic compound with Kondo scale T K ∼ 15 K and shows an enhanced Sommerfeld coefficient of γ 0 ∼ 203 mJ/mol·K 2 . While no superconductivity can been observed down to 30 mK, Ce ions exhibit two successive antiferromagnetic (AFM) transitions. We propose that the magnetic moment of Ce ion could align in the G type AFM order below the first transition at T N 1 =9.3 K, and it might be modified into the C type AFM order below a lower transition at T N 2 =7.3 K. Our results indicate that the 3d-4f interlayer Kondo interactions play an important role in Ni-based Ce-containing pnictide.

Kramers non-magnetic superconductivity inLnNiAsO superconductors

“…In this paper, we have independently synthesized and investigated a series of LnNiAsO (Ln = La, Ce, Pr, Nd, Sm) compounds. Both LaNiAsO and CeNiAsO have been studied in previous literatures [12,13,15]. The new material SmNi-AsO is obtained and undergoes an AFM transition at 3.5 K. Nd-NiAsO keeps paramagnetic down to 2 K but exhibits the local AFM phase transition below 1.3 K. These results also indicate that the magnetism in LnNiAsO system is only attributed to the rare earth elements.…”

“…Compared with the counterpart LnFeAsO [19,20], we note that a-axis of LnNiAsO is slightly longer than that of LnFeAsO, c-axis is much shorter. The reduction of c-axis in LnNiAsO is expected to strengthen the interlayer coupling, which plays an important role in the enhancement of the Kondo effect in CeNiAsO [15]. Figure 2(a) shows the temperature dependence of resistivity ρ(T ) of LnNiAsO (Ln = La, Ce, Pr, Nd, Sm) from 0.4 K to 300 K. The inset shows the enlarged plot below T 4 K. For all the samples, the resistivity falls monotonically with temperature decreasing and no anomaly associated with magnetic phase transition can be observed at a high temperature region.…”

Magnetism and crystalline electric field effect in ThCr2Si2-type CeNi2AsLuo1, Bao2, Shen3 et al. 2012Phys. Rev. BSelf Cite

“…29 Owing to the absence of magnetism in the Ni sublattice, the Ce-Ni-based compounds have shown great advantage in studying the Ce-4f -electron correlation. 14,33,37,38 This also accounts to the fact that the CaBe 2 Ge 2 -type CeNi 2 As 2 is a nonmagnetic Kondo lattice because the Kondo coupling is largely enhanced by one of the inverted NiAs layer. Compared with all these cases, the ThCr 2 Si 2 -type CeNi 2 As 2 has a relatively small Kondo coupling but a moderately strong magnetic frustration.…”

“…CeAs, NiAs, and NaAs were presynthesized as mentioned elsewhere. 14,15 CeAs, NiAs, CeO 2 , 16 and Ni were weighted in the ratio of 1:1:1:1, thoroughly ground in an argon-filled glove box. The mixture was then put into a Ta tube, together with 15 molar times of NaAs.…”

Heavy-fermion quantum criticality and destruction of the Kondo effect in a nickel oxypnictide

“…The heavy-fermion behavior crucially depends on the delicate interplay between the 3d-and 4f -electrons [11]; indeed, the presence of the 3d-electron antiferromagnetic (AFM) order in the FeAs layer complicates the study of the 4f electrons. We therefore turn to CeNiAsO, the Ni counterpart of the parent iron pnictides, in which the 3d electrons are shown to be magnetically disordered based on the measurements of entropy and magnetic susceptibility [12].The compound CeNiAsO is homology to the well-studied CeFeAsO[6] of the ZrCuSiAs crystalline structure. The absence of AFM order on the Ni sublattice was confirmed both theoretically and experimentally [13,14].…”