The modulated structure of intermediate-valent CeCoGa
| hal.structure.identifier | Institut für Anorganische und Analytische Chemie | |
| dc.contributor.author | NIEHAUS, Oliver | |
| hal.structure.identifier | Institut für Anorganische und Analytische Chemie | |
| dc.contributor.author | HOFFMANN, Rolf-Dieter | |
| hal.structure.identifier | Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB] | |
| dc.contributor.author | CHEVALIER, Bernard | |
| hal.structure.identifier | Institut für Anorganische und Analytische Chemie | |
| dc.contributor.author | PÖTTGEN, Rainer | |
| dc.date.issued | 2016 | |
| dc.identifier.issn | 2194-4946 | |
| dc.description.abstractEn | CeCoGa was synthesized by melting of the elements in an arc-melting furnace as well as in a sealed niobium tube in an induction furnace. A further annealing step improves the purity and crystallinity of the samples significantly. Its structure was refined on the basis of single-crystal X-ray diffractometer data at different temperatures. Already at room temperature CeCoGa crystallizes in a superstructure of the HT-CeCoAl type. This superstructure can be described in the (3+1)D superspace group C2/m(α0γ)00; α=2/3, γ=1/3 with a temperature independent q-vector (Z=4). For the 300 K data (also for 90 K) the commensurate modulated structure could be refined with 1336 F2 values, 56 variables and residuals of wR=0.0348 for the main and wR=0.0605 for the satellites of 1st order [a=1101.7(1), b=436.0(1) and c=482.4(1) pm, β=103.2(1)°]. Furthermore a description in a transformed 3D supercell with the space group C2/m and Z=12 is possible. For the 90 K data this 3D supercell was refined with 1289 F2 values, 56 variables and a residual of wR=0.0409 [a=1618.8(1), b=435.3(1) and c=1094.1(1) pm, β=119.3(1)°]. The relation of the HT-CeCoAl type structure, the (3+1)D modulated and the 3D supercell structure are discussed on the basis of a group-subgroup relation. By thermal analysis and magnetic measurements the phase transition temperature to the HT-CeCoAl type structure is stated slightly above 475 K. Furthermore intermediate cerium valence was identified by the magnetic susceptibility. | |
| dc.language.iso | en | |
| dc.publisher | De Gruyter | |
| dc.subject.en | cerium | |
| dc.subject.en | group-subgroup scheme | |
| dc.subject.en | intermediate valence compound | |
| dc.subject.en | modulated structure | |
| dc.title.en | The modulated structure of intermediate-valent CeCoGa | |
| dc.type | Article de revue | |
| dc.identifier.doi | 10.1515/zkri-2015-1882 | |
| dc.subject.hal | Chimie/Chimie inorganique | |
| dc.subject.hal | Chimie/Cristallographie | |
| bordeaux.journal | Zeitschrift für Kristallographie - Crystalline Materials | |
| bordeaux.page | 143-153 | |
| bordeaux.volume | 231 | |
| bordeaux.issue | 3 | |
| bordeaux.peerReviewed | oui | |
| hal.identifier | hal-01288004 | |
| hal.version | 1 | |
| hal.popular | non | |
| hal.audience | Internationale | |
| hal.origin.link | https://hal.archives-ouvertes.fr//hal-01288004v1 | |
| bordeaux.COinS | ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Zeitschrift%20f%C3%BCr%20Kristallographie%20-%20Crystalline%20Materials&rft.date=2016&rft.volume=231&rft.issue=3&rft.spage=143-153&rft.epage=143-153&rft.eissn=2194-4946&rft.issn=2194-4946&rft.au=NIEHAUS,%20Oliver&HOFFMANN,%20Rolf-Dieter&CHEVALIER,%20Bernard&P%C3%96TTGEN,%20Rainer&rft.genre=article |
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