Abstract

The study of ordered arrays of magnetic nanostructures is a topic that has attracted considerable interest due to their promising technological applications mainly in high-density information storage. In order to reach this objective it is necessary to investigate in detail the stable magnetic configurations in function on the aspect ratio of magnetic cylinders, the reversion mechanisms of the magnetization in nanowires, the influence of magnetostatic interactions among nanowires and nanodots, and in general, the behavior of the magnetic properties as function of different structural parameters. Different fabricating methods of ordered arrays of nanostructures are avaliable. Among these, the method of two step anodization and template-based electrochemical process is widely used because it is simple, inexpensive technique, fast and allow some control of important structural parameters. On the other side, the investigation of electric transport properties of magnetic materials is a topic that is of great interest in the field of sensors. The study of magnetoresistance and Hall effect is also very important on the point of view of basic research since these effects are closelly related to the magnetic properties of the materials. In last years I have been interested in the study of the magnetic and trans- port properties of magnetic thin films and nanostructures. I have been working in magnetic films producced by sputtering and composed by small magnetic nanoparticles and/or by magnetic thin multilayers. These materials can have in- teresting properties as giant magnetoresistance, giant extraordinary Hall Effect and superparamagnetism. More recentlly I have been working in the magnetic characterization of arrays of nanowires that are producced by electrodeposition inside ordered pores of alumina membranes. In this proposal I want to fabri- cate new magnetic structures using a combination of different techniques as an- odization, electrodeposition and sputtering. We have started the fabrication of ordered porous alumina membranes in the first semester of this year and at this moment we are working with the anodization parameters to control the diame- ter of the pores. We want to fabricate arrays of pores with different diameters and fill them with nanowires, segmented nanowires and nanotubes. Sputtering will be used to fabricate films on top of the nanopores and the nanowires. The main objective is to obtain new materials with improved magnetotrans- port properties (magnetoresistance and Hall Effect) wich have a clear applied perspective, and with interesting magnetic properties that can be studied both experimentally and theoretically.