The magnetic structures of RMgSn compounds (R = Ce, Pr, Nd, Tb)

TitleThe magnetic structures of RMgSn compounds (R = Ce, Pr, Nd, Tb)
Publication TypeJournal Article
Year of Publication2011
AuthorsRitter C, Provino A, Manfrinetti P, Gschneidner KA
Journal TitleJournal of Alloys and Compounds
Volume509
Pages9724-9732
Date Published10
Type of ArticleArticle
ISBN Number0925-8388
Accession NumberWOS:000295978500004
Keywordscenisn, cepdsn, ceptsn, crystal structure, magnetic ordering, magnetic structure, neutron diffraction, neutron-diffraction, rare-earth compounds, Rare-earth magnesium stannides
Abstract

The synthesis of the new compounds RMgSn (R = La-Nd, Sm, Gd-Tm, Lu and Y) has been recently reported. The compounds formed by La and Ce crystallise in the TiNiSi structure type (oP12, Pnma), while from Nd they adopt the CeScSi-type (tI12, I4/mmm); PrMgSn is dimorphic: its high-temperature form (HT) is TiNiSi-type while the low-temperature one (LT) is CeScSi-type. In this paper we now report the results of a neutron diffraction investigation which has been performed in order to refine the crystal as well as the magnetic structures for the RMgSn compounds with R = Ce, Pr, Nd and Tb. All these compounds see at low temperature the establishment of long range magnetic ordering with a predominantly antiferromagnetic interaction; only PrMgSn-HT orders ferromagnetically. These results agree with those from magnetic measurements recently reported. The magnetic structure of CeMgSn is of the amplitude-modulated type, the value of the magnetic propagation vector refined at 2 K is tau = [0, 0.1886(4), 0.3384(8)]. The PrMgSn-HT phase below T = 52 K adopts first a purely ferromagnetic structure, then at about T = 15 K a second magnetic coupling leads to a spin-canted magnetic structure. Both PrMgSn-LT and NdMgSn have the same antiferromagnetic commensurate magnetic structure. The TbMgSn compound below T(N) = 35 K orders antiferromagnetically with an equal moment cycloidal structure; however a second magnetic transition at a temperature corresponding to T(N2) = 65 K is likely also present. (C) 2011 Elsevier B.V. All rights reserved.

DOI10.1016/j.jallcom.2011.07.100
Alternate JournalJ. Alloy. Compd.