Magnetic Properties of Co/Pr Artificial Superlattice Thin Films Evaporated in O2 Atmosphere

Co/Pr artificial superlattice films were prepared by electron beam evaporation in O
₂
gas. The authors performed systematic investigations of the film magnetic properties, in particular (i) the dependence of the saturation magnetization M
_s
on temperature; (ii) the dependence of the perpendicular magnetic anisotropy constant K
_⊥
on temperature; and (iii) the dependence of the polar Kerr rotation angle θ
_k
on wavelength. All the hysteresis loops of Co/Pr artificial superlattice films prepared in O
₂
gas were symmetric at 300 K, but a loop shift was observed for Co/Pr artificial superlattice films prepared in O
₂
gas at 1 × 10
^-5
Torr when films were cooled to 77 K in the presence of a magnetic field. The maximum loop shift was about 1.4 kOe. The dependence of θ
_k
on wavelength for Co/Pr deposited in O
₂
gas is different from that for Co. Polar Kerr rotations were large, and the maximum value of θ
_k
was - 0.77°.