PROJECT OBJECTIVES

General objective:

The present project proposes obtaining materials having improved magnetic properties for data storage in nanoelectronics, namely an enhanced thermal stability (increased blocking temperature) for FM nanoparticles (NPs), having the small sizes imposed by the areal bit density required for the next generation devices (several nm), as well as an enhancement of magnetic coercivity. The materials to be studied will be in the form of FM NPs in AFM or ferrimagnetic matrixes or FM core/AFM or ferrimagnetic shell NPs as such or in various thin film matrixes. In order to establish whether the AFM-FM exchange bias or the interparticle interactions creating collective states are responsible for the improved magnetic properties of the materials, FM NPs will also be embedded into non-AFM matrixes and the magnetic properties of the nanocomposites will be compared with the FM/AFM systems.

Specific objectives:

• obtaining NPs having a core-shell structure, where the core is FM and the shell is AFM or ferrimagnetic will be obtained using pulsed laser ablation in a controlled gas atmosphere. The resulting core-shell structures will be characterized from the point of view of morphology, crystalline structure, composition, interface and magnetic properties.
• obtaining FM NPs embedded into AFM or ferrimagnetic matrixes using succesive laser deposition. The resulting materials will be characterized morphologically, structurally and magnetically. The same FM NPs will also be embedded in non-AFM matrixes in order to ascertain the relative importance of exchange bias or interactions in FM nanostructures (with formation of collective states) in improving the magnetic properties of the NPs.
• obtaining NPs having a FM shell and an AFM or ferrimagnetic core embedded into various matrixes. The dependence of magnetic properties of the complex structures on the core/shell NP structure, NP density and on the nature of the matrix will be analyzed.
• Post-deposition thermal annealing will be applied to the priorly obtained structures and their effects on the morphological, structural and magnetic properties of the materials will be studied.
• Obtaining of optimized nanocomposite magnetic materials having improved properties making them applicable in the next generation data storage systems (small bit size, large blocking temperature, thermal stability, stability of grains against demagnetizing field). Optimized method of obtaining the nanocomposite AFM/FM materials will also be obtained.