3000 % high-field magnetoresistance in super-lattices of CoFe nanoparticles
arXiv:0710.1750 · doi:10.1016/j.jmmm.2007.11.010
Abstract
We report on magnetotransport measurements on millimetre-large super-lattices of CoFe nanoparticles surrounded by an organic layer. Electrical properties are typical of Coulomb blockade in three dimensional arrays of nanoparticles. A large high-field magnetoresistance, reaching up to 3000 %, is measured between 1.8 and 10 K. This exceeds by two orders of magnitude magnetoresistance values generally measured in arrays of 3d metals ferromagnetic nanoparticles. The magnetoresistance amplitude scales with the magnetic field / temperature ratio and displays an unusual exponential dependency with the applied voltage. The magnetoresistance abruptly disappears below 1.8 K. We propose that the magnetoresistance is due to some individual paramagnetic moments localized between the metallic core of the nanoparticles, the origin of which is discussed.
arXiv comment9 pages (text, references, figures and legends)
References in corpus (4)
- Collective Transport in Arrays of Quantum Dots
- Percolating through networks of random thresholds: Finite temperature electron tunneling in metal nanocrystal arrays
- Transport in Magnetic Nanoparticles Super-Lattices : Coulomb Blockade, Hysteresis and Magnetic Field Induced Switching
- Coulomb gap, Coulomb blockade, and dynamic activation energy in frustrated single-electron arrays