MAGNETOOPTICAL ENHANCEMENT IN PT (NI1-XCOX) MULTILAYERS/

Magneto-optical (MO) polar Kerr rotation (PKR) and ellipticity (PKE) s pectra of Pt/(Ni1-xCox) multilayers with x = 0, 0.3 and 1 nm prepared by evaporation under ultrahigh-vacuum conditions were studied. The thi ckness of the Pt layer was kept between 1.5 and 2 nm, and that of the (Ni1-xCox) alloy layer, t(Ni1-xCox), was 0.45 and 1.4 nm. Layers forme d at the Pt-magnetic layer interfaces give rise to a surface-induced p erpendicular magnetic anisotropy (PMA) and to an enhancement of PKR in the near-UV spectral region. Because the Curie temperature T-C is clo se to 300 K for x = O a clear manifestation of these effects in the Ni /Pt system required cooling to low temperatures. The possibility to op timize the characteristics, like PMA, T-C and the amplitude and positi on of the PKR peak in the spectra by proper choices of x, t(Pt) and t( Ni1-xCox) makes Pt/(Ni1-xCox) multilayers interesting for the realizat ion of MO storage media capable of working in blue light.