Magnetic relaxation in nano-particle stacks

AP Robinson, PJD Southern, W Schwarzacher

Research output: Contribution to journalArticle (Academic Journal)peer-review

4 Citations (Scopus)

Abstract

The remanent magnetisation and magnetic relaxation of Ni-Cu/Cu superlattice nanowires have been investigated. Arrays of superlattice nanowires were prepared by template deposition through polycarbonate nanoporous membranes using a single electrolyte bath. The thicknesses of nickel-rich layers (tNi) and copper layers (tCu) were independently controlled by monitoring the current during deposition. A study of the remanent magnetisation at 5K for tNi) = 30Å and a range of values of tCu reveals the existence of inter-layer demagnetising interactions within each array. However the demagnetising interaction strength appears to reach a minimum level, believed to be due to intra-layer interactions caused by island formation within nickel-rich layers. Magnetic relaxation measurements on the same arrays after removal of a saturating (5T) field at various temperatures show M to decrease linearly with ln(t). The data were analyzed using the Tln(t0) scaling technique, revealing the effective energy barrier distribution of the arrays to be constructed of two components, possibly due to non- (or weakly-) interacting particles and strongly-interacting particles respectively. The weakly-interacting component is observed to decrease with decreasing tCu and is believed to be caused by large individual nickel islands (corresponding to inter-layer interactions), while the strongly-interacting component is believed to be due to fragmented nickel islands (corresponding to intra-layer interactions).
Translated title of the contributionMagnetic relaxation in nano-particle stacks
Original languageEnglish
Pages (from-to)16 - 19
JournalJournal of Physics: Conference Series
Volume17
DOIs
Publication statusPublished - 2005

Bibliographical note

Editors: Pankhurst Q
Publisher: Institute of Physics Publishing
Name and Venue of Conference: 5th International Conference on Fine Particle Magnetism, UCL London, Sept. 2004
Conference Organiser: Institute of Physics

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