Peculiarities of the intermediate valence state of Ce in CeM2Si2 (M=Fe, Co, Ni) compounds

Influence of chemical composition on the X-ray photoemission, thermopower, specific heat, and magnetic properties of CeNi2(Si1-yGey)2

“…It implies that the Ce valence is stable for all the compositions with the Ge content above 0.25. The significant deviation of the lattice constants for the parent CeNi 2 Si 2 compound may be ascribed to its well confirmed fluctuating valence state [2,6,7]. Similar valence evolution has been observed for other isostructural series of alloys, e.g., Ce(Ni 1-x Cu x ) 2 Si 2 [16,17].…”

“…For FV system a large value of T K is expected. In various estimates provided in literature it varies in the range 400-1200 K for the parent CeNi 2 Si 2 compound [2,6,7].…”

“…While CeNi 2 Si 2 is a well confirmed fluctuating valence (FV) system [2,6,7], the behaviour of the HF CeNi 2 Ge 2 indicates on exotic behaviours like NFL and superconductivity [8][9][10][11][12][13][14][15]. It is due to the proximity of this compound to the antiferromagnetic Quantum Critical Point (QCP).…”

Anomalous Behavior on Specific Heat and Thermoelectric Power in Wide Range of Temperatures in CeNi2(Ge1-xSix)2

“…8,9) Here, we present experimental results of S and C m for polycrystalline CeNi 2 (Ge 1−x Si x ) 2 up to room temperature (RT), and investigate the correlation between them in a wide range of temperatures. Since CeNi 2 Si 2 is an intermediate valence (IV) material with the high Kondo temperature T K reported as 700 K or 1400 K, 10,11) the partial substitution by Si on Ge in CeNi 2 Ge 2 is expected to raise T K greatly. 7) Therefore, the substitution can provide the evolution from HF to IV state in the present * Present address: Tateyama Kagaku Industry Co., Ltd., Toyama 930-1305, Japan † E-mail address: kuwai@sci.u-toyama.ac.jp systems.…”

Antiferromagnetic Kondo lattice to intermediate valence transition in Ce(Au1−Ni )2Si2 (0≤x≤1)

“…The cerium transition-metal (T) silicides CeT 2 Si 2 have attracted particular interest for their wide variety of magnetic ground state such as antiferromagnetic (AF) ordering in CeAu 2 Si 2 [1][2][3], heavyfermion superconductivity in CeCu 2 Si 2 [4], and intermediate valence (IV) in CeNi 2 Si 2 [5]. These intermetallic compounds have the tetragonal ThCr 2 Si 2 -type structure with space group I4/mmm [6].…”