Hysteresis loop of ferromagnetic materials are measured by using surface magneto-optic Kerr effect, and the Kerr rotation Angle is obtained.
用表面磁光克尔效应测量铁磁材料的磁滞回线，并求得在饱和状态下的克尔旋转角。
2
So the conventional magneto-optical recording median, rare earth-transition metal (Re-Tm) alloys, is limited, because of its small Kerr rotation in the region of short wavelength.