Volume 88, Number 5, December 2009
|Number of page(s)||5|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||07 December 2009|
High-temperature ferromagnetism of Li-doped vanadium oxide nanotubes
Institute for Solid State Research, IFW Dresden - 01171 Dresden, Germany, EU
2 Zavoisky Physical-Technical Institute of RAS - 420029 Kazan, Russia
3 IFP, TU Dresden - D-01069 Dresden, Germany, EU
4 Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut - CH-5232 Villigen PSI, Switzerland
Corresponding author: email@example.com
Accepted: 9 November 2009
The nature of a puzzling high-temperature ferromagnetism of doped mixed-valent vanadium oxide nanotubes reported earlier by Krusin-Elbaum et al., Nature, 431 (2004) 672, has been addressed by static magnetization, muon spin relaxation, nuclear magnetic and electron spin resonance spectroscopy techniques. A precise control of the charge doping was achieved by electrochemical Li intercalation. We find that it provides excess electrons, thereby increasing the number of interacting magnetic vanadium sites, and, at a certain doping level, yields a ferromagnetic-like response persisting up to room temperature. Thus we confirm the surprising previous results on the samples prepared by a completely different intercalation method. Moreover our spectroscopic data provide first ample evidence for the bulk nature of the effect. In particular, they enable a conclusion that the Li nucleates superparamagnetic nanosize spin clusters around the intercalation site which are responsible for the unusual high-temperature ferromagnetism of vanadium oxide nanotubes.
PACS: 75.20.-g – Diamagnetism, paramagnetism, and superparamagnetism / 75.75.+a – Magnetic properties of nanostructures / 73.22.-f – Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals
© EPLA, 2009
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.