Magnetic and magneto-optical properties of Ni Pt multilayers with perpendicular magnetic anisotropy at room temperature

Abstract

The magnetic and magneto-optical properties of Ni/Pt multilayers exhibiting square Kerr hysterisis loops at room temperature were studied. Squared polar Kerr hysterisis loops at room temperature in Ni/Pt multilayer thin films were obtained for the samples prepared by sequential DC magnetron sputter deposition of nickel and platinum with t(Ni) = 13-21 Angstrom and t(pt) = 3.5-7.5 Angstrom. The coercivity of these multilayers was in the range of 400-1100 Oe. The saturation magnetization was found to show an inverse dependence on the nickel sublayer thickness. About a monolayer of Ni at interface was observed to behave less magnetically than the interior Ni atoms. The polar Kerr rotation exhibited an increasing trend with decreasing wavelength in the spectral range of 7000-4000 A. The maximum of the polar Kerr rotation was found to shift to a higher wavelength with increasing nickel sublayer thickness. (C) 1999 Elsevier Science B.V. All rights reserved.