Relationship between ThMn12 and Th2Ni17 structure types in the YFe11−<i>x</i>Ti<i>x</i> alloy series

Abstract

A series of YFe11−xTix alloys with x=0.10, 0.25, 0.40, 0.50, 0.70, 1.00, 1.25, 1.50, and 2.00 have been investigated using x-ray diffraction, thermomagnetic analysis, the singular point detection technique, and 57Fe Mössbauer spectroscopy. A pure ThMn12 -type phase was observed when 0.7≤x≤1.25. It has Curie temperature of 524 K, anisotropy field of 2.3 T, and average iron magnetic moment of 1.47 μB at room temperature. The relationship between the CaCu5 and the Th2Ni17 or ThMn12 structure types is discussed in terms of substitution of transition-metal dumbbells on Ca sites, and a structural explanation is given for the directions of the iron anisotropy in the 2:17 and 1:12 compounds.