Phys. Rev. B 63, 012407 (2000) [4 pages]Electron paramagnetic resonance spectra near the spin-glass transition in iron oxide nanoparticlesReceived 17 April 2000; published 12 December 2000 Electron paramagnetic resonance (EPR) in iron-oxide nanoparticles (∼2.5 nm) embedded in a polyethylene matrix reveals the sharp line broadening and the resonance field shift on sample cooling below TF≈40K. At the same temperature a distinct anomaly in the field-cooled magnetization is detected. The temperature dependences of EPR parameters below TF are definitely different than those found for various nanoparticles in the superparamagnetic regime. In contrast to canonical bulk spin glasses, a linear fall-off of the EPR linewidth is observed. Such behavior can be explained in terms of the random-field model of exchange anisotropy. © 2000 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevB.63.012407
DOI:
10.1103/PhysRevB.63.012407
PACS:
75.50.Lk, 75.50.Tt, 76.30.-v
|
|
About | Terms and Conditions | Subscriptions | Search | Help
Use of the American Physical Society websites and journals implies that the user has read and agrees to our Terms and Conditions and any applicable Subscription Agreement. Physical Review®, Physical Review Letters®, Reviews of Modern Physics®, and Physical Review Special Topics® are trademarks of the American Physical Society.