RESUMO
The probability laws associated to domain wall depinning under fields and currents have been studied in NiFe and FePt nanowires. Three basic domain wall depinning processes, associated to different potential landscapes, are found to appear identically in those systems with very different anisotropies. We show that these processes constitute the building blocks of any complex depinning mechanism. A Markovian analysis is proposed, that provides a unified picture of the depinning mechanism and an insight into the pinning potential landscape.
RESUMO
We describe novel features of the induced magnetic anisotropy in Co nanoclusters coupled with a CoO(111) layer. Individual cluster magnetism was studied using new microbridge superconducting quantum interference devices. Intrinsically, the Co clusters are single domains with an effective anisotropy constant K(F)≈1.5×10(6) erg·cm(-3). A bistable state of the ferromagnetic-antiferromagnetic coupling is revealed, with a maximum bias systematically observed along CoO[10 Ì 1] and an interfacial coupling energy of 0.9 erg·cm(-2). The small bias observed in cluster assembly results from an averaging over the two opposite stable states.
RESUMO
We report on the high yield connection of single nano-objects as small as a few nanometres in diameter to separately elaborated metallic electrodes, using a 'table-top' nanotechnology. Single-electron transport measurements validate that transport occurs through a single nano-object. The vertical geometry of the device natively allows an independent choice of materials for each electrode and the nano-object. In addition ferromagnetic materials can be used without encountering oxidation problems. The possibility of elaborating such hybrid nanodevices opens new routes for the democratization of spintronic studies in low dimensions.
