MAGNETIC AND MAGNETOOPTICAL STUDIES IN CO-TB PT MULTILAYERS/

We have prepared Co86Tb14/Pt multilayers by r.f. sputtering and studie d their magnetic and magneto-optical properties. As the Co-Tb layer th ickness (t(CoTb)) decreases bellow 200 Angstrom the saturation magneti zation increases, the rectangularity of the M-H loops and the coercivi ty decrease. The effective anisotropy K-eff of the multilayers was det ermined by a torque magnetometer. The product K-eff x t(CoTb) shows a linear dependence with t(CoTb) as normally found for the superlattices yielding the bulk and surface anisotropies of 1 x 10(6) erg cm(-3) an d - 0.2 erg cm(-2), respectively. These results are explained in terms of an interfacial Co-Pt layer. The polar Kerr rotation for the multil ayers is found independent of layer thickness and is equal to 11.5 min , which is higher than the single thick layer. (C) 1998 Elsevier Scien ce Ltd. All rights reserved.