Resumen de Magnetization processes of magnetic modulated nanowires

Ester María Palmero Rodríguez

• Magnetic nanowires have been proposed to be an interesting alternative in a broad spectrum of applications, such as high density magnetic storage, semiconductors, sensors, logic circuits or biomedicine, among others. The nanowire composition and geometry can be tuned to obtain specific magnetic properties, needed for each application.

  This thesis focuses on the study of magnetization processes of magnetic modulated nanowires: FeCo-based nanowires modulated in composition and in diameter. The research work gathers the nanowire arrays fabrication and their characterization, on both nanowire arrays and individual nanowires.

  Firstly, the magnetic properties of FeCo alloy nanowires were studied in the full range of composition and for several nanowire diameters. Furthermore, the effects on their magnetic properties by the addition of a small amount of Cu together with thermal treatments was determined.

  The modulation in composition was performed by fabricating multilayer nanowires intercalating Cu layers between FeCoCu segments. The influence of the geometry on the magnetization reversal of the nanowire array, together with the magnetostatic interactions in the system have been studied.

  Nanowires with tailored geometrical modulations along their length were synthesized and the magnetization reversal processes and domain structure of individual nanowires were determined, suggesting a possible way for controlling the domain wall motion by tuning the nanowires shape and magnetocrystalline anisotropy.

  Moreover, the applicability of magnetic nanowire arrays has been demonstrated by the development of two sensing devices.