Authors: J. Neamtu, M. Volmer, R.V. Medianu
Affilation: National Institute for Research&Development in Electrical Engineering, Romania
Pages: 242 - 245
Keywords: magnetotransport, magnetic, nano-structure, magnetoresistance, Hall effect
The investigation of magnetotransport and tunnel effect of magnetic nanostructures plays an important role in design of micro&nanosystems for spintronics. The nano-structures as FM/NM/FM/AFM were deposited by magnetron-sputtering on the oxidized Si wafers, as continuous films and cross-stripe structures. FM (Ferro-Magnetic) denotes NiFe (Py), Co or a combination using Py-Co layers. NM (Non-Magnetic) denotes Cu or Al2O3 layers. AFM (Anti-Ferro-Magnetic) denotes FeMn or IrMn thin film layers. These nano-structures present anisotropic magnetoresistance (AMR) and tunnel magnetoresistance (TMR). On the unpatterned films we made magnetoresistance (MR) and Anomalous Hall Effect (AHE)  in order to study the magnotransport properties of the samples and the quality of the surfaces . The effective thicknesses of the oxide layers were estimated by tunnel effect measurements and compared with in situ quartz microbalance measurements. AFM topography of surfaces shows sharp columnar grains that are growing perpendicular to the film surface. Due to low pressure of the Ar gas and the presence of a low amount of O2 in the deposition chamber, our samples obtained by sputtering method present intermixed regions of FM and NM layers. On the other hand we obtained a Giant Hall Effect for our samples, which can be attractive for magnetic sensors.