Template-based synthesis of nanotube and nanowire ferrofluids and their magnetoviscosity

• Applicants: Professor Carl Emil Krill III, Ph.D.; Professor Dr. Kornelius Nielsch
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2012 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 199968846

In this proposed continuation of a project from DFG Priority Program SPP 1165 “Nanowires and Nanotubes,” the Nielsch group will extend the atomic layer deposition (ALD) preparation route to encompass multilayered magnetic nanotubes manifesting superparamagnetic behavior. Two growth strategies will be followed to obtain the superparamagnetic state - formation of nanolaminates and decomposition of a ternary oxide - and the Krill group will optimize post-deposition annealing procedures to tailor the desired final microstructure. In addition, a new approach to the mass production of ferromagnetic nanorods will be developed by the Nielsch group based on alternating electrochemical deposition of magnetic and nonmagnetic layers into a nanoporous matrix from a single bath. Selective dissolution of the matrix and the nonmagnetic spacer segments will release huge quantities of intact ferromagnetic nanorods (up to 1013-14 per batch), the aspect ratio of which can be varied between 0.3 and 20 by adjusting the magnetic layer thickness. The Krill group will measure the magnetoviscosity of nanotube, nanowire and hybrid (nanotube+nanosphere) ferrofluids, and, together with the Kaiser group in Ulm, elucidate the microstructure of the magnetic constituents using electron tomography and energy-filtered transmission electron microscopy.

• DFG Programme: Research Grants