the result agrees well with the pre

the result agrees well with the previous reports [9–11]. It is of interest to notice a corresponding reduction in Tc with the Cr substitutions. This
strongly indicates that the Cr atoms enter into the lattice of Co11Zr2
and result in the band structure change of 3d electrons [5,6].
Fig. 3 displays the magnetization at 20 kOe r20, remanence rr,
and coercivity iHc of as-spun Co80ÿxZr18CrxB2 (x = 0, 2, 3, and 4).
For x = 0, r20 of 65 emu/g, rr of 43.5 emu/g and iHc of 3.1 kOe are
achieved. Adjustment of the Cr content does have a large influence
on the magnetic properties. We can see that r20 and rr decrease
with Cr substitutions. However, iHc increases from 3.1 kOe for
x = 0 to a peak value of 5.3 kOe for x = 3 and then there is a decrease
with the further increase of Cr content. It has been reported that a
suitable heat treatment has beneficial effect on the coercivity
enhancement [3,4,7]. In order to obtain a higher coercivity, the
as-spun Co80ÿxZr18CrxB2 (x = 0, 2, 3, and 4) ribbons are annealed
at temperatures ranging from 500 °C to 700 °C spaced 50 °C apart
for 2 min. Fig. 4 shows the dependence of iHc on the annealing temperature. One can notice that iHc of all the four samples shows a
similar change trend; it first increases to a peak value after a suitable heat treatment and then gradually decreases with the further
increase of annealing temperature. The maximum iHc of 7.0 kOe is
realized in the sample with x = 3 after annealed at 550 °C. Compared to the highest iHc of 5.1 kOe ever obtained in the Co80Zr18B2