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Journal ArticleDOI

Magnetic properties and magnetic structures of the CeScSi-type RMgPb (R¼Ce-Nd, Sm, Gd-Tm) compounds

01 Sep 2012-Journal of Magnetism and Magnetic Materials (North-Holland)-Vol. 324, Iss: 19, pp 2937-2952
TL;DR: In this paper, powder X-ray diffraction, magnetic measurements and neutron powder diffraction on the CeScSi-type ternary magnesium plumbides RMgPb (R=Ce-Nd, Sm, Gd-Tm) are reported.
About: This article is published in Journal of Magnetism and Magnetic Materials.The article was published on 2012-09-01. It has received 7 citations till now. The article focuses on the topics: Paramagnetism & Magnetization.
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Journal ArticleDOI
TL;DR: A free web page under the name MAGNDATA, which provides detailed quantitative information on more than 400 published magnetic structures, has been made available at the Bilbao Crystallographic Server (http://www.cryst.ehu.es).
Abstract: A free web page under the name MAGNDATA, which provides detailed quantitative information on more than 400 published magnetic structures, has been made available at the Bilbao Crystallographic Server (http://www.cryst.ehu.es). It includes both commensurate and incommensurate structures. In the first article in this series, the information available on commensurate magnetic structures was presented [Gallego, Perez-Mato, Elcoro, Tasci, Hanson, Momma, Aroyo & Madariaga (2016). J. Appl. Cryst. 49, 1750–1776]. In this second article, the subset of the database devoted to incommensurate magnetic structures is discussed. These structures are described using magnetic superspace groups, i.e. a direct extension of the non-magnetic superspace groups, which is the standard approach in the description of aperiodic crystals. The use of magnetic superspace symmetry ensures a robust and unambiguous description of both atomic positions and magnetic moments within a common unique formalism. The point-group symmetry of each structure is derived from its magnetic superspace group, and any macroscopic tensor property of interest governed by this point-group symmetry can be retrieved through direct links to other programs of the Bilbao Crystallographic Server. The fact that incommensurate magnetic structures are often reported with ambiguous or incomplete information has made it impossible to include in this collection a good number of the published structures which were initially considered. However, as a proof of concept, the published data of about 30 structures have been re-interpreted and transformed, and together with ten structures where the superspace formalism was directly employed, they form this section of MAGNDATA. The relevant symmetry of most of the structures could be identified with an epikernel or isotropy subgroup of one irreducible representation of the space group of the parent phase, but in some cases several irreducible representations are active. Any entry of the collection can be visualized using the online tools available on the Bilbao server or can be retrieved as a magCIF file, a file format under development by the International Union of Crystallography. These CIF-like files are supported by visualization programs like Jmol and by analysis programs like JANA and ISODISTORT.

67 citations


Cites background from "Magnetic properties and magnetic st..."

  • ...See, for instance, the case of HoMgPb (MAGNDATA reference #1.1.32; Lemoine et al., 2012), where the third and fifth harmonics have been refined....

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Journal ArticleDOI
TL;DR: In this article, the equiatomic CeXX′ phases (X and X′ = elements of the 3ʳᵈ, 4ᵃ, or 5ᵃ main group) extend the large series of CeTX intermetallics (T = electron-rich transition metal).
Abstract: The equiatomic CeXX′ phases (X and X′ = elements of the 3ʳᵈ, 4ᵗʰ, or 5ᵗʰ main group) extend the large series of CeTX intermetallics (T = electron-rich transition metal). These phases crystallize with simple structure types, i.e. ZrNiAl, TiNiSi, CeScSi, α-ThSi₂, AlB₂, and GdSi₂. In contrast to the CeTX intermetallics one observes pronounced solid solutions for the CeXX′ phases. The main influence on the magnetic ground states results from the absence of d electrons. All known CeXX′ phases show exclusively trivalent cerium and antiferro- or ferromagnetic ordering at low temperatures. The crystal chemical details and some structure-property relationships are reviewed.

14 citations

Journal ArticleDOI
TL;DR: It is shown for the first time for this family of materials that hydrogen insertion reduces the dimensionality of the magnetic and transport properties from 3D to quasi-2D which results in a vanishing of the ferromagnetic order and a change of the metallic conduction behavior to a nonmetallic one.
Abstract: Intermetallic phases have been investigated with respect to their ability to accept small atoms in interstitial sites without changing the host structure. Among those, the intermetallic compounds c...

8 citations

Journal ArticleDOI
TL;DR: In this paper, the physical properties of rare-earth-gold equiatomic R-Au intermetallics (R= Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) are explored.

7 citations

Journal ArticleDOI
TL;DR: Magnetic symmetry analysis shows that the canted structure would not be allowed in the I4/mmm space group; this result further confirms the structural transition and suggests a magnetostructural origin of this structural distortion.
Abstract: An investigation on the ground state magnetism of CeScSi, CeScGe (tetragonal CeScSi-type, tI12, space group I4/mmm) by temperature-dependent powder neutron diffraction has been carried out, as debated and controversial data regarding the low temperature magnetic behaviours of these two compounds were reported. Our studies reveal that, while cooling, long-range magnetic ordering in CeScSi and CeScGe takes place by a two-step process. A first transition leads to a magnetic structure with the Ce moments aligned ferromagnetically onto two neighbouring tetragonal basal a-b planes of the CeScSi-type structure; the double layers are then antiferromagnetically coupled to each other along the c-axis. The transition temperature associated with the first ordering is T N ~ 26 K and T N ~ 48 K for the silicide and the germanide, respectively. Here the spin directions are rigorously confined to the basal plane, with values of the Ce magnetic moments of μ Ce = 0.8-1.0 μ B. A second magnetic transition, which takes place at slightly lower temperatures, results in a canting of the ordered magnetic moments out of the basal plane which is accompanied by an increase of the magnetic moment value of Ce to μ Ce = 1.4-1.5 μ B. Interestingly, the second magnetic transition leads to a structural distortion in both compounds from the higher-symmetry tetragonal space group I4/mmm to the lower-symmetry and triclinic I-1 (non-standard triclinic). Magnetic symmetry analysis shows that the canted structure would not be allowed in the I4/mmm space group; this result further confirms the structural transition. The transition temperatures T S from I4/mmm to I-1 are about 22 K in CeScSi and 36 K in CeScGe, i.e. well below the temperature of the first onset of antiferromagnetic order observed in this work (or below the ordering temperature, previously reported as either T C or T N). This result, along with the synchronism of the magnetic and structural transitions, suggests a magnetostructural origin of this structural distortion. We have also carried out powder neutron diffraction for LaScSi as a non-magnetically-ordering reference compound and compared the results with those of CeScSi and CeScGe compounds.

7 citations

References
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Journal ArticleDOI
TL;DR: In this article, the main formulas governing the analysis of the Bragg magnetic scattering are summarized and shortly discussed and the method of profile fitting without a structural model to get precise integrated intensities and refine the propagation vector(s) of the magnetic structure is discussed.
Abstract: In spite of intrinsic limitations, neutron powder diffraction is, and will still be in the future, the primary and most straightforward technique for magnetic structure determination. In this paper some recent improvements in the analysis of magnetic neutron powder diffraction data are discussed. After an introduction to the subject, the main formulas governing the analysis of the Bragg magnetic scattering are summarized and shortly discussed. Next, we discuss the method of profile fitting without a structural model to get precise integrated intensities and refine the propagation vector(s) of the magnetic structure. The simulated annealing approach for magnetic structure determination is briefly discussed and, finally, some features of the program FullProf concerning the magnetic structure refinement are presented and discussed. The different themes are illustrated with simple examples.

11,923 citations

MonographDOI
TL;DR: In this paper, the authors introduce magnetostatics and magnetism of localized electrons on the atom, and apply it to spin electronics and magnetic recording, as well as applications of hard magnets.
Abstract: 1. Introduction 2. Magnetostatics 3. Magnetism of electrons 4. Magnetism of localized electrons on the atom 5. Ferromagnetism and exchange 6. Antiferromagnetism and other magnetic order 7. Micromagnetism, domains and hysteresis 8. Nanoscale magnetism 9. Magnetic resonance 10. Experimental methods 11. Magnetic materials 12. Applications of soft magnets 13. Applications of hard magnets 14. Spin electronics and magnetic recording 15. Special topics Appendixes Index.

3,137 citations

Journal ArticleDOI
TL;DR: In this paper, a calculation of the indirect exchange type coupling of nuclear magnetic moments in a metal by means of the hyperfine interaction with the conduction electrons was given, which appears to account qualitatively for the broad nuclear spin resonance lines observed in natural metallic silver.
Abstract: A calculation is given of the indirect exchange ${\mathrm{I}}_{i}\ifmmode\cdot\else\textperiodcentered\fi{}{\mathrm{I}}_{j}$ type coupling of nuclear magnetic moments in a metal by means of the hyperfine interaction with the conduction electrons. The interaction appears to account qualitatively for the broad nuclear spin resonance lines observed in natural metallic silver. It is expected that the interaction may sharpen the resonances in pure isotopic specimens. The line shape of the minority isotope in a binary mixture may tend to be Gaussian, while that of the majority isotope may tend to be Lorentzian, if the indirect exchange interaction is dominant.

2,716 citations

Journal ArticleDOI
TL;DR: In this paper, the polarization of conduction electrons due to the first order perturbed energy corresponding to the Fr\"ohlich-Nabarro and Zener mechanism was investigated and it was shown that the polarization is concentrated in the neighborhood of the Mn ions.
Abstract: The polarization of conduction electrons due to $s\ensuremath{-}d$ interaction in CuMn alloys is investigated. The uniform polarization due to the first order perturbed energy corresponding to the Fr\"ohlich-Nabarro and Zener mechanism is shown to be completely modified by the first order perturbation of the wave functions and the polarization is concentrated in the neighborhood of the Mn ions. At the same time it is shown that the Fr\"ohlich-Nabarro interaction is included in the Ruderman-Kittel result as one component. The electronic $g$-value of Mn ions and the Knight shift of the Cu-nuclei are also discussed from this point of view.

2,274 citations

Journal ArticleDOI
Tadao Kasuya1
TL;DR: In this article, the T3/2 law for the temperature dependence of the magnetization of ferromagnetism is shown to be applicable up to very high temperatures, and this result is in good agreement with the results of experiments on metallic ferromagnetic magnetization.
Abstract: The importance to the mechanism of ferromagnetim of exchange interaction between conduction electrons and unfilled inner shell electrons (called s-d interaction) has been pointed out by Zener. Especially for rare earth metals, this interaction seems to be the only mechanism which can cause ferroand antiferromagnetism. However Zener's works are unsatistisfactory because his model is phenomenological and moreover does not involve antiferromagnetism and spin wave mode. Our paper considers this s-d interaction on a more rigorous basis. By a certain approximation, there appear long range eychange type interactions between d-electron spins and, in certain conditions both ferroand antiferromagnetism appear. The excitations of spin wave modes are the same as those in the ordinary modes of the short range exchange force, viz, the energy of the spin wave excitations is proportional to q2 for ferromagnetism and q for antiferromagnetism in the region of small wave vector q. The T3/2 law for the temperature dependence of the magnetization of ferromagnetism is applicable up to very high temperatures, and this result is in good agreement with the results of experiments on metallic ferromagnetism.

1,988 citations