Existence and properties of Co-rich 3:29-type of compounds synthesized with heavy rare earths

Journal of Magnetism and Magnetic Materials Volume 316, Issue 2 SPEC. ISS., September 2007, Pages e458-e461

Efthimiadis, K.G., Sarafidis, C. Gjoka, M., Kalogirou, O.

Abstract

In this work, the synthesis and the study of rare earth-transition metal intermetallic compounds with nominal stoichiometry R₃(Fe_1-xCo_x)_29-yCr_y (R=Tb, Ho and (x, y)=(0.6, 4.5) and (0.8, 5.5)) is presented. The compounds were synthesized with the typical arc-melting technique from high-purity constituents and subsequently annealed at various temperatures. Both series were found to produce practically single-phase samples after the annealing procedure with a significant difference in crystal structure. For R=Tb, the monoclinic 3:29 phase (Nd₃(Fe, Ti)₂₉-type, space group A2/m) is produced, while for R=Ho, a disordered variant of the hexagonal 2:17 phase (Th₂Ni₁₇-type, space group P6₃/mmc) occurs. The magnetic interactions for the samples with x=0.8 are generally weaker than those with less Co, especially in the case of R=Ho. The magnetocrystalline anisotropy of all the compounds has a planar character.