Electric and Magnetic Properties of Iron Manganese Silicide Nanowires
Matos, Angela Luis
Fonseca, Luis (Consejero)
Magnetic nanowires displaying ferromagnetic properties have received tremendous scientific attention owing to their potential applications for magnetic storage and spintronic nanodevices. Room temperature ferromagnetic semiconducting Fe1-xMnxSi nanowires were synthesized from a multiple source precursors (MSPs) over silicon substrate by Chemical Vapor Deposition (CVD) without the use of a catalyst. Scanning electron microscope (SEM) images showed high density of as grown nanowires with slightly rough surfaces with diameters between 50 and 200 nm and tens of micrometers in length. X-rays diffraction (XRD) and selected area electron diffraction (SAED) patterns showed high quality crystalline order of Fe1-xMnxSi nanowires that can be ascribed to the cubic B20 crystal structure. The presence of Mn ions in Fe1-xMnxSi was confirmed by energy-dispersive X-ray spectroscopy (EDS). Characteristic ferromagnetic hysteresis loops were obtained by Vibrating Sample Magnetometry (VSM). Besides, to confirm the ferromagnetism in the nanowires Magnetic Force Microscopy (MFM) was used to scan the magnetic domains in the nanowires. The electrical resistance of single nanowires was obtained from the slopes of I-V curves measured with specialized four-probes microdevices. The calculated resistivity is consistent with previous reported values and the temperature dependence of the conductivity shows thermal activation which is attributed to the semiconductor properties of the material.