Hard magnetic properties of Sm-Co-Cu-Fe single phase 2-17 bulk samples

Sm(Co
0.08
Cu
0.13
)
z
alloys were prepared with
7.2 \leq z < 8
. Homogenization heat-treatment yielded single phase 2-17 material for
z > 7.2
. For
z = 7.8
some of the Co was substituted by Fe. The alloys remained single phase for up to 15 % Co substituted. With further increasing Fe content a Co-Fe phase appears accompanied by a strong decrease of the hard magnetic properties. The compounds were hard magnetic in bulk form with ideal rectangular hysteresis loops. The coercivity could be increased by a factor > 2 with a low temperature heat-treatment. B
R
values > 11 kG together with
I
H
c
values of about 4 kOe were achieved on single crystal samples. The coercivity mechanism in these materials is pinning of Bloch walls.