Paper PL-TuP9
Optical, Magnetic and Magneto-Optical Properties of Noble-Metal/Ferromagnet Nano-Composite Materials

Tuesday, October 16, 2007, 6:00 pm, Room 4C

Magnetic nanoparticles embedded in noble metal thin films exhibit interesting properties that are function of the microstructure and can be used in relevant applications. Some of these materials can be processed further to achieve a particular magnetic anisotropy of interest while others may exhibit plasmonic enhancement of their optical properties that can be used in a variety of sensing applications, in particular biosensing. The optical, magnetic and magneto-optical properties of these nano-composite materials depend on the materials used, the nano-particle size and distribution, the inter-particle distance, etc. We will present our studies on such composite materials in thin film form. In particular, we will show that ion-implantation of ferromagnetic metal ions onto noble metal thin films is a powerful tool for nano-fabrication of embedded nano-clusters with controlled geomety, i.e. size and distribution. We will present our studies applied to two such systems: FePt and AuCo. In the former case, we have also used thermal treatments to achieve the L10 phase of interest in new generation perpendicular magneto-recording media. In the latter case, we were particularly interested in the enhancement of the surface plasmon resonance (SPR) of the noble metal when combined with a ferromagnetic one, i.e. a magneto-plasmonic material. We will compare the SPR response of a Au/Co/Au trilayer in which the optical response can be tailored varying the thickness of the Co layers, with a nano-composite material made with Co magnetic nano-clusters embedded on a Au thin film matrix. In this latter case, the Co clusters are ion-implanted onto the Au matrix and their size and penetration depth can be tailored by choosing the ion-implantation conditions. We will show our field dependent SPR data on this nanocomposite material.