Agradecimentos: This work was financially supported in part by the Fonds Quebecois de Recherche sur la Nature et les Technologies (FQRNT), Canada, the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), Brazil, and the Spanish Government MICINN and EU FEDER under research projects nos MAT2009-13108-C02-01, MAT2010-20798-C05-04 and FICYT No FC-09-IB09-131. Small-angle x-ray scattering data was acquired at beamline D11A-SAXS1 at Laboratorio Nacional de Luz Sincroton (LNLS). We acknowledge Professor Cotta (UNICAMP) for the AFM measurements. MK acknowledges the Brazilian agency CNPq and the John Simon Guggenheim Memorial Foundation for the Guggenheim Fellowship 2009-2010 Ver menos

Abstract: A simple method to quantitatively characterize the local magnetic behaviour of a patterned nanostructure, like a ferromagnetic thin film of antidot arrays, is proposed. The first-order reversal curve (FORC) analysis, coupled with simulations using physically meaningful hysterons, allows us to obtain a quantitative and physically related description of the interaction field and each magnetization reversal process. The hysterons system is built from previously known hypotheses on the magnetic behaviour of the sample. This method was successfully applied to a highly hexagonal ordered FePd antidot array with nanometric dimensions. We achieved a complete characterization of the two different magnetization reversal mechanisms in function of the in-plane applied field angle. For a narrow range of high fields, the magnetization initiates rotating reversibly around the pores, while at lower fields, domain walls are nucleated and propagated. This in-plane magnetization reversal mechanism, partly reversible and partly irreversible, is the only angularly dependent one. While going away from the easy axis, its reversible proportion increases, as well as its switching field distribution. Finally, the results indicate that the high surface roughness between adjacent holes of the antidot thin film induces a parallel interaction field. The proposed method demonstrates its ability also to be applied to characterizing patterned nanostructures with rather complex magnetization reversal processes Ver menos