Crystal structure transformation in CeRuSn seen via the atomic pair distribution function

Prokeš, K.; Kimber, Simon A. J.; Mydosh, J. A.; Pöttgen, Rainer

doi:10.1103/physrevb.89.064106

Cited by 9 publications

(13 citation statements)

References 19 publications

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“…The 2c structure is reported to be replaced by various structural modifications, the dominant mode being a tripling of the basic CeCoAl cell (the 3c structure). Nevertheless, our recent synchrotron x-ray work showed that the 3c structure is only an approximation to the real crystal structure of CeRuSn [13]. However, neither of the literature sources could solve the details of the low temperature crystal (and hence also the AF structure) unambiguously.…”

Section: Introductionmentioning

confidence: 98%

(3 + 1)-dimensional crystal and antiferromagnetic structures in CeRuSn

Prokeš¹,

Petřı́ček²,

Ressouche³

et al. 2014

J. Phys.: Condens. Matter

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Abstract. At 320 K, the crystal structure of CeRuSn is commensurate with the related CeCoAl type of structure by the doubling of the c lattice parameter. However, with lowering the temperature it becomes incommensurate with x and z position parameters at all three elemental sites being modulated as one moves along the c-axis. The resulting crystal structure can be conveniently described within the superspace formalism in (3+1) dimensions. The modulation vector, after initially strong temperature dependence, approaches a value close to q nuc = (0 0 0.35). Below T N = 2.8 (1) K, CeRuSn orders antiferromagnetically with a propagation vector q mag = (0 0 0.175), i.e. with the magnetic unit cell doubled along the c-axis direction with respect to the incommensurate crystal structure. Ce moments appear to be nearly collinear, confined to the a − c plane, forming ferromagnetically coupled pairs. Their magnitudes are modulated between 0.11 and 0.95 µ B as one moves along the c-axis.

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Section: Introductionmentioning

confidence: 98%

(3 + 1)-dimensional crystal and antiferromagnetic structures in CeRuSn

Prokeš¹,

Petřı́ček²,

Ressouche³

et al. 2014

J. Phys.: Condens. Matter

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“…Unfortunately, we were unable to determine structural details of our crystal at room temperature (these are available for 10 K [14]). For analysis of data taken at 285 K we have therefore utilized parameters determined from our previous x-ray single crystal diffraction and neutron powder diffraction that are in good agreement with structural information obtained by other groups [9,10,13,17]. This high-temperature crystal structure of CeRuSn projected nearly along the b axis is shown in Fig.…”

Section: B Spin Density At 285 Kmentioning

confidence: 87%

“…Since the modulation is close to a tripling of the original CeCoAl structure along the c axis, we have used the three times larger c-axis parameter. The positional parameters were taken from literature [10,13,17]. This leads to three independent Ce, Ru, and Sn sites.…”

Section: Spin Density At 2 Kmentioning

confidence: 99%

“…Below room temperature, a hysteretic structural phase transformation occurs in CeRuSn that is visible from temperature dependencies of various physical properties including the electrical resistivity, thermal expansion, and magnetic susceptibility [7,9,10,12,13]. Earlier diffraction experiments were interpreted that the 2c structure is replaced by other structural modifications whose volume fractions are * prokes@helmholtz-berlin.de temperature and history dependent.…”

Section: Introductionmentioning

confidence: 99%

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Coexistence of different magnetic moments in CeRuSn probed by polarized neutrons

et al. 2015

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General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. We report on the spin densities in CeRuSn determined at elevated and at low temperatures using polarized neutron diffraction. At 285 K, where the CeRuSn crystal structure contains two different crystallographic Ce sites, we observe that a Ce site with larger nearest-neighbor distances is clearly more susceptible to the applied magnetic field, whereas the other is hardly polarizable. This finding clearly documents that different local environment of the two Ce sites causes the Ce ions to split into magnetic Ce 3+ and nonmagnetic Ce (4−δ)+ valence states. With lowering the temperature, the crystal structure transforms to a structure incommensurately modulated along the c axis. This leads to new inequivalent crystallographic Ce sites resulting in a redistribution of spin densities. Our analysis using the simplest structural approximant shows that in this metallic system Ce ions coexist in different valence states. Localized 4f states that fulfill the third Hund's rule are found to be close to the ideal Ce 3+ state (at sites with the largest Ce-Ru interatomic distances), whereas Ce (4−δ)+ valence states are found to be itinerant and situated at Ce sites with much shorter Ce-Ru distances. The similarity to the famous γ -α transition in elemental cerium is discussed.

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“…Further details on the structure refinement are available from Fachinfor- short Ce-Ru distances, first observed for CeRuSn [36][37][38] and several aluminides [39], gallides [40] and indides [41]. The intermediate-valent character of cerium in these intermetallics has been manifested by temperature dependent magnetic susceptibility stud-…”

Section: Structure Refinementmentioning

confidence: 98%