Structural study of nanocrystallized Cu83Co17 ribbons by scanning friction force microscopy

Abstract

Nanocrystallized cobalt clusters embedded in a copper matrix exhibiting giant magnetoresistance have been revealed by scanning force and friction microscopy. The microscopic images reported here should be important to understand the magnetic properties of these novel systems.

About the nature of two-dimensional formations at the polar surface of cleaved triglycine sulfate crystals

“…Thus the formation of islands and holes can be connected to the energy stability of separate layers of the crystal structure and with compensation of depolarization fields at the atomic smooth surface formed when cleaving the crystal along the cleavage plane. The possibility of such processes of redistribution of the surface charges at cleaving was mentioned in [14]. L.M.…”

“…On the contrary, J. Ohgami et al"'] determined by electrostatic force microscope combined with the voltage modulation technique that the region of the TGS surface with many small round holes and islands has a negative surface charge, and the region without holes and islands has a positive one. The investigation of TGS domain structure by lateral force microscopy, including its temperature and temporal evolution, has led A. Correia et al [14] to the deduction that the similar formations can have another nature, namely to be nuclei of opposite polarity inside large domains. There is the possibility that small round formations with various shapes are ferroelectric surface domains [23,251. It is obvious from these discrepancies, that more study of islandes and holes at the polar surface characteristic for TGS crystals is required.…”

Direct observation of cobalt precipitates in nanocrystalline Cu–Co powder synthesised by laser ablation

“…Although there are many trials to observe the microstructure of the alloy, it is very difficult to observe directly the precipitation and growth of Co particles from the supersaturated Cu-Co alloy owing to the very small Co precipitates of a few nanometers 7,8 and the very small lattice mismatch of Cu and Co (1 . 94%).…”