Demagnetization of Co-Cr films induced by stress and heat

Stress and heat induced demagnetization of Co-Cr films with perpendicular magnetic anisotropy deposited on 50 μm thick polyimide base films has been studied. The loss in remanent magnetization M
r
was detected with a vibrating sample magnetometer VSM after the film had been stressed or heated. M
r
decreases monotonically to about half, as stress increases to 4 × 10
⁹
dyn/cm
²
. Such loss in ramanence
\deltaM_{r}
with stress, however, decreases as perpendicular magnetic anisotropy field
H_{k\perp}
or film thickness increases.
\deltaM_{r}
can also be reduced by using double layer medium with soft magnetic layer. These results suggest that the higher
H_{k\perp}
and better orientation of the magnetic vector to the c-axis lead to the smaller demagnetization. Heating the films in its remanent state also leads a decrease in the remanence. M
r
reduces below 85 % by heating to a temperature of 150°C. This loss in Mr is mainly due to the decrease in perpendicular magnetic anisotropy energy.