Magnetic anisotropy of Ni/Cu sputtered multilayers L. Albini a , G. Carlotti a, * , C. Dragoni a , G. Gubbiotti a , L. Verdini a , S. Loreti b , C. Minarini b , L. Pareti c , G. Turilli c a Dipartimento di Fisica, Istituto Nazionale per la Fisica della Materia, Via Pascoli, I-06100 Perugia, Italy b C.R. ENEA, I-80055 Portici Napoli, Italy c Istituto MASPEC-CNR, Area delle Scienze, 43010 Parma, Italy Abstract Ni/Cu multilayers were grown by RF sputtering. The crystal orientation, the thickness of the elemental layers and the interface quality were analysed by X-ray diraction in the h±2h con®guration. Magnetic anisotropy was investigated by both a static and a dynamic technique, namely magneto±optical Kerr eect MOKE) and Brillouin light scattering BLS). Longitudinal MOKE loops accounted for the in-plane orientation of the magnetization, while polar loops were used to determine the out-of-plane anisotropy ®elds, showing the existence of a minor second-order contribution in addition to the ®rst-order one. BLS was then exploited to detect thermal excited spin waves through inelastic scattering of light. The out-of-plane anisotropy ®elds evaluated by this high-frequency dynamic technique compare well with the ®rst-order values obtained by analysis of polar MOKE hysteresis cycles. Ó 2001 Elsevier Science B.V. All rights re- served. Keywords: Magnetic interfaces; Nickel; Magnetic ®lms; Metal±metal magnetic heterostructures; Surface waves; Magnons 1. Introduction The theoretical interest towards the magnetic properties of arti®cially layered systems is moti- vated by the fact that the reduced dimensionality strongly modi®es their magnetic behaviour with respect to those of bulk materials [1]. Moreover, magnetic ®lms and multilayers are ®nding steadily growing application in the technology of longitu- dinal and perpendicular magnetic recording, in magneto-optic storage technology, and in the ®eld of magnetic sensors [2]. In this paper we present the results of the structural and magnetic properties of Ni/Cu mul- tilayers, with dierent values of the repetition pe- riodicity, deposited by RF sputtering on Si100) substrates. Magneto±optical Kerr eect MOKE) analysis, in both longitudinal and polar con- ®gurations, with applied ®elds up to 10 kOe, was exploited to measure hysteresis cycles and to de- termine the intrinsic magnetic anisotropy. The re- sults of the above mentioned static technique MOKE) are quantitatively compared to those obtained by Brillouin light scattering BLS) [3] which is based on the detection of thermally acti- vated high-frequency spin waves. This simulta- neous and combined use of MOKE and BLS is particularly interesting, because signi®cant dis- crepancies have been reported in the literature Surface Science 482±485 2001) 998±1003 www.elsevier.nl/locate/susc * Corresponding author. Tel.: +39-75-5853067; fax: +39-075- 44666. E-mail address: carlotti@pg.infn.it G. Carlotti). 0039-6028/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII:S0039-602800)01087-6