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Calixarene-stabilised cobalt nanoparticle rings: Self-assembly and collective magnetic properties.
- Source :
- Supramolecular Chemistry; Apr2009, Vol. 21 Issue 3/4, p189-195, 7p, 8 Diagrams
- Publication Year :
- 2009
-
Abstract
- Calixarenes can be used to promote the self-assembly of thermoremanent cobalt nanoparticles into bracelet-like rings below 100 nm in diameter. These kinetically stable assemblies are regulated by the equilibrium between enthalpic gain (dipole-dipole and long-range van der Waals interactions) and entropic loss, analogous to the thermodynamic balance of forces governing supramolecular self-assembly. Examination of the Co nanoparticle rings by electron holography (an electron microscopy technique for imaging in-plane magnetic induction) reveals the existence of chiral flux closure (FC) domains at room temperature, comprising a 'racemic' mixture of clockwise and anticlockwise states. Furthermore, these FC polarisations can be reversed by applying out-of-plane magnetic pulses (Hz) in alternating directions. This switching behaviour has no known analogy at the macroscopic level, and may represent a uniquely nanoscale phenomenon. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10610278
- Volume :
- 21
- Issue :
- 3/4
- Database :
- Complementary Index
- Journal :
- Supramolecular Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 38610538
- Full Text :
- https://doi.org/10.1080/10610270802546044