Photoemission study of the electronic structure of the Kondo latticesYb2Pt6X15(X=Al, Ga)

Magnetic Properties of theRE2Pt6X15(RE= Y, La–Nd, Sm, Gd–Lu;X= Al, Ga) Series

“…As expected, the lattice parameters decrease with the size of the rare‐earth element, in line with the lanthanide contraction. The lattice parameters of Yb 2 Pt 6 Al 15 almost fit the trend suggesting Yb 3+ atoms, which was confirmed by magnetic susceptibility measurements (vide infra) and was also reported in the literature . For the gallide series RE 2 Pt 6 Ga 15 , the lattice parameters for RE = La–Nd, Sm, Eu–Lu were determined in the literature, however, they were just depicted in a graph and no values were reported.…”

“…No superconductivity was observed for these samples. For Gd 0.67 Pt 2 Al 5 (≡ Gd 2 Pt 6 Al 15 ), antiferromagnetic ordering at a Néel temperature of T N = 7.5 K and 8 K was reported, single crystals of Yb 2 Pt 6 Al 15 were found to exhibit a broad maximum at low temperatures, in line with a Kondo lattice system with a large degeneracy of the local moments . For the heavier homologue Ga, also some compounds with the RE 0.67 Pt 2 Ga 5 / RE 2 Pt 6 Ga 15 composition ( RE = La, Ce, Pr, Nd, Sm, Gd, Er,) have been reported to crystallize in the Sc 0.6 Fe 2 Si 4.9 type structure.…”

“…Pr 2 Pt 6 Ga 15 (reported as Pr 1.33 Pt 4 Ga 10 ) has recently been reinvestigated and ferrimagnetism was found below T = 12.5(5) K . Furthermore, magnetic susceptibility measurements and X‐ray photoelectron spectroscopic (XPS) investigations of the Kondo compounds Yb 2 Pt 6 Al 15 , , and Yb 2 Pt 6 Ga 15 have been reported , , . The overall susceptibilities for Yb 2 Pt 6 Ga 15 are small and nearly directional independent, in contrast to paramagnetic Yb 2 Pt 6 Al 15 , which contains solely trivalent Yb atoms.…”

Electronic structure of YbFe$_4$Al$_8$ antiferromagnet: A combined X-ray photoelectron spectroscopy and first-principles study

“…It is not uncommon to put the same material into both categories based on similar experimental results, where a well-known example is YbAl 3 [12][13][14]. A valence band, similar to the one observed for YbFe 4 Al 8 [15], consisting of contributions from Yb 2+ and Yb 3+ has been seen previously for both materials classified as valence fluctuating, such as YbCu 2 Si 2 [16], YbAl 2 [17,18], YbB 12 [19], Yb 2 Pt 6 Ga 15 and Yb 2 Pt 6 Al 15 [20], as well as for materials of intermediate valence, such as YbFe 4 Sb 12 [21], YbInCu 4 [22], YbNi 0.8 Al 4.2 [23], YbRh 2 Si 2 [11], Yb 4 Ga 24 Pt 9 [24], and Yb 2 Si 2 Al [10]. Since our experimental analysis is based solely on XPS measurements, we cannot unambiguously resolve the membership of the compound under consideration, YbFe 4 Al 8 , in the class of fluctuating or intermediate valence materials.…”

“…A structure similar to the triple one seen in Fig. 2 has been observed, for example, for Yb 2 Pt 6 Al 15 [20]. A one way to discard the signal from the surface would be to use hard X-rays with photon energy on the order of a few keVs [20].…”