Self-Assembly Processes of Polymer Cobalt Microwire Composites Synthesised by Chemical Deposition with Hydrazine
G. Mamniashvili *
Andronikashvili Institute of Physics at Ivane Javakhishvili Tbilisi State University, 6 St. Tamarashvili, 0177 Tbilisi, Georgia.
T. Gegechkori
Andronikashvili Institute of Physics at Ivane Javakhishvili Tbilisi State University, 6 St. Tamarashvili, 0177 Tbilisi, Georgia.
M. Janjalia
Andronikashvili Institute of Physics at Ivane Javakhishvili Tbilisi State University, 6 St. Tamarashvili, 0177 Tbilisi, Georgia.
T. Zedginidze
Andronikashvili Institute of Physics at Ivane Javakhishvili Tbilisi State University, 6 St. Tamarashvili, 0177 Tbilisi, Georgia.
T. Petriashvil
Andronikashvili Institute of Physics at Ivane Javakhishvili Tbilisi State University, 6 St. Tamarashvili, 0177 Tbilisi, Georgia.
R. Kezerashvili
New York City College of Technology the City University of New York, 300 Jay St, Brooklyn, NY 11201, USA.
*Author to whom correspondence should be addressed.
Abstract
Magnetic micro- and nanomaterials with controlled morphology and size are of significant importance for the fabrication of nanoscale devices and advanced functional materials. Among these, cobalt-based microstructures are particularly attractive due to their pronounced magnetic dipole moments and strong response to external magnetic fields, which induce alignment along the field direction. A comparative study of self-organisation processes in magnetic polymer microwire composites doped with cobalt microwires was conducted. The microwires were synthesised by chemical deposition using hydrazine in an external magnetic field and compared with commercial cobalt microwires. Self-organisation arises from the diffusion and polarisation of magnetic nanoparticles stimulated by a constant magnetic field. It was studied using nuclear magnetic resonance (NMR) and magnetometry. Magnetisation inversion is accompanied by an increase in magnetic susceptibility, enhancement of the NMR echo signal intensity, and acceleration of the transverse relaxation rate of two-pulse echoes. A weakening of these effects was observed in cobalt micropowder-based polymer composites. The echo signal amplification effect in the case of synthesised microwires is much greater than that of commercial nanowires, which may be due to the lower pinning force of domain walls and their greater mobility in them. The resulting polymer composites show promise for practical applications.
Keywords: Cobalt microwires, polymer microwire composites, self-organisation, NMR, magnetometry