Structure Refinement and Magnetic Properties of Ce2RuAl3 and a Group-Subgroup Scheme for Ce5Ru3Al2

Mishra, Trinath; Hoffmann, Rolf‐Dieter; Schwickert, Christian; Pöttgen, R.

doi:10.5560/znb.2011.66b0771

Cited by 27 publications

(21 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is different for the Ce1 atoms. The smaller effective size of almost tetravalent Ce1 leads to drastically shortened Ce1-Ru distances of 233 and 246 pm, also observed in many intermetallics based on Ce and Ru [21,22]. These are a consequence of strong covalent Ce1-Ru bonding [7], the strongest bonding interactions in the CeRuSn structure.…”

Section: Crystal Chemistry and Course Of The Solid Solutionsmentioning

confidence: 99%

The Solid Solutions (Ce_1-xLa_x)RuSn

Niehaus

Chevalier

Abdala

et al. 2013

Zeitschrift Für Naturforschung B

View full text Add to dashboard Cite

X-Ray-pure samples of the solid solutions (Ce 1−x La x )RuSn were obtained up to x = 0.5. Powder diffraction data show the CeRuSn-type superstructure up to x ≈ 0.3 and the CeCoAl-type subcell for higher lanthanum contents. The structure of a single crystal with x = 0.5 was refined on the basis of single-crystal X-ray diffractometer data: CeCoAl type, C2/m, a = 1160.8(2), b = 477.6(1), c = 511.6(1) pm, β = 102.97(2) • , wR = 0.0510, 444 F 2 values, 20 variables. Magnetic investigations were performed for all samples up to a lanthanum content of x = 0.4. No cooperative phenomena could be observed, and all samples show Curie-Weiss behavior above a certain temperature. The cerium valence is about 3.32(2) for all samples of the solid solution. Hence, La 3+ has to replace Ce 3+ as well as Ce 4+ in a particular quantity. The electrical resistivity measurements confirm the suppression of the magnetic ordering and the structural transition upon replacement of cerium by lanthanum. 119 Sn Mössbauer spectra of samples with x = 0.2 and 0.5 are indicative of single tin sites with isomer shifts of δ = 1.86(1) mm s −1 for x = 0.2 and δ = 1.88(1) mm s −1 for x = 0.5. Both signals are subject to significant quadrupole splitting, a consequence of the low site symmetry. Results of XANES measurements are perfectly in line with the cerium valences determined by susceptibility measurements and yield a constant value of 3.16(1) for all investigated compounds.

show abstract

Section: Crystal Chemistry and Course Of The Solid Solutionsmentioning

confidence: 99%

The Solid Solutions (Ce_1-xLa_x)RuSn

Niehaus

Chevalier

Abdala

et al. 2013

Zeitschrift Für Naturforschung B

View full text Add to dashboard Cite

show abstract

“…This ternary stannide belongs to a larger class of compounds with extremely short Ce-Ru distances [20,21] which are a consequence of almost tetravalent cerium. CeRuSn crystallizes with a commensurate superstructure of the monoclinic CeCoAl type and adopts complex modulations at lower temperature.…”

Section: Introductionmentioning

confidence: 99%

Cerium Valence Change in the Solid Solutions Ce(Rh_1-xRux)Sn

Niehaus

Abdala

Riecken

et al. 2013

Zeitschrift Für Naturforschung B

View full text Add to dashboard Cite

The solid solutions Ce(Rh 1−x Ru x )Sn were investigated by means of susceptibility measurements, specific heat, electrical resistivity, X-ray absorption spectroscopy (XAS), and 119 Sn Mössbauer spectroscopy. Magnetic measurements as well as XAS data show a cerium valence change in dependence on the ruthenium content. Higher ruthenium content causes an increase from 3.22 to 3.45 at 300 K. Furthermore χ and χ −1 data indicate valence fluctuation for cerium as a function of temperature. For example, Ce(Rh 0.8 Ru 0.2 )Sn exhibits valence fluctuations between 3.42 and 3.32 in the temperature range of 10 to 300 K. This could be proven by using the interconfiguration fluctuation (ICF) model introduced by Sales and Wohlleben. Cerium valence change does not influence the tin atoms as proven by 119 Sn Mössbauer spectroscopy, but it influences the electrical properties. Ce(Rh 0.9 Ru 0.1 )Sn behaves like a typical valence fluctuating compound, and higher ruthenium content causes an increase of the metallic behavior.

show abstract

“…The latter two materials are members of an interesting series of cerium-rutheniumbased compounds that are characterized by a mixture of Ce ions with long and extraordinarily short Ce-Ru bonds on inequivalent Ce sites. The latter bonds can be as short as 2.23Å, much shorter than the sum of the covalent radii of Ce and Ru (2.89Å) [8,9].…”

mentioning

confidence: 99%

Valence modulations in CeRuSn

et al. 2014

Self Cite

View full text Add to dashboard Cite

CeRuSn exhibits an extraordinary room temperature structure at 300 K with coexistence of two types of Ce ions, namely trivalent Ce 3+ and intermediate valent Ce (4−δ)+ , in a metallic environment. The ordered arrangement of these two Ce types on specific crystallographic sites results in a doubling of the unit cell along the c-axis with respect to the basic monoclinic CeCoAl-type structure. Below room temperature, structural modulation transitions with very broad hysteresis have been reported from measurements of various bulk properties. X-ray diffraction revealed that at low temperatures the doubling of the CeCoAl type structure is replaced by a different modulated ground state, approximating a near tripling of the basic CeCoAl cell. The transition is accompanied by a significant contraction of the c axis. We present new x-ray absorption near-edge spectroscopy data at the Ce L 3 absorption edge, measured on a freshly cleaved surface of a CeRuSn single crystal. In contrast to a previous report, the new data exhibit small but significant variations as function of temperature that are consistent with a transition of a fraction of Ce 3+ ions to the intermediate valence state, analogous to the γ → α transition in elemental cerium, when cooling through the structural transitions of CeRuSn. Such results in a valence-modulated state.

show abstract

Structure Refinement and Magnetic Properties of Ce2RuAl3 and a Group-Subgroup Scheme for Ce5Ru3Al2

Cited by 27 publications

References 0 publications

The Solid Solutions (Ce_1-xLa_x)RuSn

The Solid Solutions (Ce_1-xLa_x)RuSn

Cerium Valence Change in the Solid Solutions Ce(Rh_1-xRux)Sn

Valence modulations in CeRuSn

Contact Info

Product

Resources

About

Structure Refinement and Magnetic Properties of Ce2RuAl3 and a Group-Subgroup Scheme for Ce5Ru3Al2

Cited by 27 publications

References 0 publications

The Solid Solutions (Ce1-xLax)RuSn

The Solid Solutions (Ce1-xLax)RuSn

Cerium Valence Change in the Solid Solutions Ce(Rh1-xRux)Sn

Valence modulations in CeRuSn

Contact Info

Product

Resources

About

The Solid Solutions (Ce_1-xLa_x)RuSn

The Solid Solutions (Ce_1-xLa_x)RuSn

Cerium Valence Change in the Solid Solutions Ce(Rh_1-xRux)Sn