Structural disorder and magnetism in rare-earth (R) R117Co54+xSn112 +/- y

TitleStructural disorder and magnetism in rare-earth (R) R117Co54+xSn112 +/- y
Publication TypeJournal Article
Year of Publication2013
AuthorsMudryk Y, Manfrinetti P, Smetana V, Liu J, Fornasini ML, Provino A, Pecharsky VK, Miller GJ, Gschneidner KA
Journal TitleJournal of Alloys and Compounds
Volume557
Pages252-260
Date Published04
Type of ArticleArticle
ISBN Number0925-8388
Accession NumberWOS:000315185000040
Keywords773 k, co-sn system, compound, crystal structure, crystal-structure, DY, Electrical transport, magnetic properties, r=gd, Rare earth cobalt stannides, refinement, stannides, ternary-system, TM
Abstract

The cubic R117Co54+xSn112 +/- y compounds (R = La-Lu, except Pm, Eu, and Yb) have been synthesized and characterized using X-ray diffraction and magnetization measurements. The existence of the compounds with R = Ce, Pr, Sm, Gd, Tb, and Dy has been confirmed, while new compounds with R = Y, La, Nd, Ho, Er, Tm, and Lu have been discovered. All of the studied phases adopt the Dy117Co57Sn112-type crystal structures with a giant cubic cell (a similar to 30 angstrom) when the proper heat treatment regime was selected. The lattice parameter decreases from La to Lu, in accordance with the lanthanide contraction and indicating the trivalent state for Ce in Ce117Co54.5Sn115.2. The Co/Sn compositional ratio increases when the size of the R atoms decreases. A single crystal investigation of Gd117Co56.4Sn114.3 confirms extensive structural disorder, particularly around the (1/2, 1/2, 1/2) location of the unit cell (4b site). Such disorder leads to an elongation of the thermal ellipsoids for the atoms surrounding this location. The magnetic measurements of the compounds with R = Ce, Gd and Tb indicate weak magnetic interactions and non-collinear alignment of magnetic moments in the ordered state. The electrical resistivity of Gd117Co56.4Sn114.3 shows interesting behavior with a change of sign at T-C for the d rho/dT parameter. (C) 2013 Elsevier B.V. All rights reserved.

URL<Go to ISI>://WOS:000315185000040
DOI10.1016/j.jallcom.2012.12.137