MAGNETIC ANISOTROPY AND MAGNETOTRANSPORT PROPERTIES OF NANOSTRUCTURED Fe-Pt THIN FILMS

The study of magnetic and electrical characteristics of some nanostructured magnetic thin layers has fundamental importance to understand magnetization dynamics and is related to applications in magneto-electronics devices. This paper is devoted to the investigation of Fe-Pt alloy films with the aim to obtain by electrolysis nanostructured films with GMR effect. The Fe-Pt samples were prepared onto polycrystalline Cu substrates using electrodeposition with controlled potential, from a solution containing: K2PtCl6, Fe(NH4)2(SO4)2. 6H2O, H3BO3 and NaCl. The samples were characterised by torsion magnetometry, by an induction method, by SEM and EDAX. The studied samples showed uniaxial anisotropy perpendicular to the plane of the film. The nanostructured FexPt1-x films, with x ≈ 30 – 38 % and granular morphology exhibit large values of the magnetoresistance (of about 11 % in current perpendicular-to-plane configuration). Such electrodeposited alloys near to stoichiometric concentration FePt3, are composed from antiferromagnetic clusters in addition to ferromagnetic ones, i. e. a mixed ferro- antiferro-magnetic state. The local concentration fluctuations generated during the film preparation results in a spatially inhomogeneous magnetic structure