title: Synthesis and properties of new multinary silicides R5Mg5Fe4Al(x)Si(18-x) (R = Gd, Dy, Y, x ≈ 12) grown in Mg/Al flux.
abstract: Reactions of iron, silicon, and R = Gd, Dy, or Y in 1:1 Mg/Al mixed flux produce well-formed crystals of R(5)Mg(5)Fe(4)Al(x)Si(18-x) (x ≈ 12). These phases have a new structure type in tetragonal space group P4/mmm (a = 11.655(2) Å, c = 4.0668(8) Å, Z = 1 and R(1) = 0.0155 for the Dy analogue). The structure features two rare earth sites and one iron site; the latter is in monocapped trigonal prismatic coordination surrounded by silicon and aluminum atoms. Siting of Al and Si was investigated using bond length analysis and (27)Al and (29)Si MAS NMR studies. The magnetic properties are determined by the R elements, with the Gd and Dy analogues exhibiting antiferromagnetic ordering at T(N) = 11.9 and 6.9 K respectively; both phases exhibit complex metamagnetic behavior with varying field.
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, USA.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Ma
authors.forename: Banghao
authors.initials: B
authors.lastname: Chen
authors.forename: Susan E
authors.initials: SE
authors.lastname: Latturner