Effects of the individual particle relaxation time on superspin glass dynamics
2016 (English)In: PHYSICAL REVIEW B, ISSN 2469-9950, Vol. 93, no 5, 054407Article in journal (Refereed) PublishedText
The low temperature dynamic magnetic properties of two dense magnetic nanoparticle assemblies with similar superspin glass transition temperatures T-g similar to 140 K are compared. The two samples are made from batches of 6 and 8 nm monodisperse gamma-Fe2O3 nanoparticles, respectively. The properties of the individual particles are extracted from measurements on reference samples where the particles have been covered with a thick silica coating. The blocking temperatures of these dilute assemblies are found at 12.5 K for the 6 nm particles and at 35 K for the 8 nm particles, which implies different anisotropy energy barriers of the individual particles and vastly different temperature evolution of their relaxation times. The results of the measurements on the concentrated particle assemblies suggest a strong influence of the particle energy barrier on the details of the aging dynamics, memory behavior, and apparent superspin dimensionality of the particles.
Place, publisher, year, edition, pages
2016. Vol. 93, no 5, 054407
Condensed Matter Physics Engineering and Technology
IdentifiersURN: urn:nbn:se:uu:diva-279564DOI: 10.1103/PhysRevB.93.054407ISI: 000369726000001OAI: oai:DiVA.org:uu-279564DiVA: diva2:908420
FunderSwedish Research Council