Síntesis y caracterización de nanoestructuras de SmCo

ELISA HERRERA; JULIETA RIVA; SILVIA URRETA; LUIS FABIETTI

Rosario

Encuentro; XV Encuentro de Superficies y Materiales Nanoestructurados NANO 2015.; 2015

Our main interest is the development of unidimensional magnetic nanostructures based on the Sm-Co system, with good hydrogen storage properties and efficient reaction mechanisms at room temperature. In this first stage we report the synthesis procedures and the structural and magnetic properties of the resulting nanotube (NT) arrays. The nanotubes were DC electrodeposited into the cylindrical pores of a commercial alumina sieve. Electrodeposition potentials between -2,0 V and -3,0 V were explored. The phases present in the NTs were investigated by X-ray diffraction techniques while the nanotubes morphology and the resulting composition, Co97.5Sm2.5, were determined by SEM and EDS, respectively. The XRD diagrams suggest that the alloy is a disordered alloy hcp Co(Sm), but the observed lines are too small and broad to state any conclusion. This feature may be attributed to small grain size, close to the detection limit of this technique. The NT arrays are ferromagnetic and relatively soft; they exhibit a moderate shape anisotropy, but the dependence of coervivity on the angle  between the applied magnetic field and the long NT axis is not monotonic; coercivity goes through a local maximum near 70 degrees, probably due to a change in the polarization reversal mechanism, from one controlled by the nucleation of a vortex domain wall to another one, involving nucleation of a transverse domain wall in the NT.