Easy directions of magnetization in ternary R2(Co, Fe)17phases

The magnetocrystalline symmetry and the Curie temperature of six families of quasi-binary rare earth-cobalt-iron intermetallic phases were studied. Investigated were the phases R
2
(Co
1-x
Fe
x
)
17
of the light rare-earth elements R = Ce, Pr, Nd, Sm, and Y and also of Ce-rich mischmetal (MM). In the Sm system, the terminal compound Sm
2
Co
17
has an easy c axis and the easy-axis symmetry persists up to
x \approx 0.5
. The Nd alloys have an easy basal plane for all values of x. In the other systems, small iron substitutions change the easy-plane behavior of the R
2
Co
17
to an easy-axis anisotropy. The easy-axis ranges are
x \approx 0.05
to 0.45 for Ce,
x \approx 0.2
to 0.6 for Pr,
x \approx 0.1
to 0.5 for Y, and
x \approx 0.1
to 0.45 for MM. The Curie temperatures are high, between 600°C and 940°C, in these ranges. It is concluded that some of the alloys investigated are promising candidate materials for use in improved "rare earth-cobalt" magnets.