CRYSTAL STRUCTURE AND MAGNETIC ANISOTROPY OF Sm₂(Fe,V)_17+δ

Abstract

The crystal structure and magnetic anisotropy of Sm2(Fe,V) 17+ <5' which is one of the novel compounds identified as RiFe,M)17+ <5 (M=Ti,V ,Mo,W) by the authors, were investigated. The structure type of Sm 2 (Fe,V)17+ <5 was determined by electron diffraction and Rietveld analysis of XRD data. Sm 2 (Fe,Vh7+!5 has a monoclinic structure with the space group P2 1 /c. the same as Nd3(Fe,Tih9' and with a periodicity based on 5 folds of the CaCus-type unit cell. The lattice parameters are a=I.056nm, b=0.852nm, c=0.969nm, {3 =96.82° . The unit cell of this compound has 4e and 2a rare earth sites, which are equivalent to 6c site in Th 2 Zn 17 structure and 2a site in ThMn12 structure, respectively. The easy direction for magnetization of Sm 2 (Fe,V)17+<5 is on the (102) plane, which coincides with the c-plane of CaCu s . This anisotropy can be mainly governed by the local anisotropy of 4e site rare earth.

The Space Group of Nd3Fe29-xTix: A2/m or P21/c

“…So they thought, that the R 3 Fe 29Àx M xtype structure was A2/m, because the symmetry of A2/m was higher than that of P2 1 /c. But in 1998, supporting to the first view, Kataoka et al [9] thought, that R 2 (Fe,M) 17þd and R 3 Fe 29Àx M x had the same structure in the space group P2 1 /c.…”