SYNTHESIS AND MICROSTRUCTURE OF FREESTANDING MAGNETIC NANOWHISKER

Changing dimensions towards smaller sizes into the nanometer regime has the prospect to change also the materials properties. This is due the increasing effect of surfaces and defects as dislocations and interfaces compared to the bulk properties. A decreasing defect density leads for example to a increase of mechanical yield stress as already demonstrated. Also the magnetic domain structure is expected to be influenced by reducing dimensions. We demonstrate the synthesis of Co, Ni and Fe nanowhiskers on Mo and W substrates. Typical dimensions of the nanowhiskers are: length 10 µm, diameters 100 nm. Transmission electron microscopy studies revealed the microstructure of the nanowhiskers and electron holography magnetic domain structure. The geometrical shape of the nanostructures dominates the domain structure and all three magnetic materials exhibit a single domain with the magnetisation direction parallel to the axis of the nanowhisker. Changing the aspect ratio towards 1 changes also the magnetisation direction to the easy directions.