Effects of size and interactions on the magnetic behaviour of elliptical (0 0 1)Fe nanoparticles

• Published in: Journal of magnetism and magnetic materials Vol. 316; no. 2; pp. 181 - 183
• Main Authors: Hanson, M., Bručas, R., Kazakova, O.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 2007; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Fe elliptical particle; Magnetic domain; Magnetic properties and materials; Magnetic properties of nanostructures; Magnetic switching; Physics; 75.50.Bb; Fe elliptical particle; Magnetic switching; 75.70.Kw; Magnetic domain; Magnetization reversal; Electron beam lithography; Iron; Fe elliptical particle; Magnetic domain; Magnetic switching; Magnetic force microscopy; Ion beams; Thickness; Nanoparticles; Magnetic domains; Size effect; 75.50.Bb; 75.70.Kw; Demagnetization; Exchange interactions
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2007.02.185

Arrays of elliptical particles with aspect ratio 1:3 and short axes 50, 100 and 150 nm were prepared by electron-beam lithography and ion-beam milling of epitaxial (0 0 1)Fe films of thicknesses 10 and 20 nm. The domain state of an individual particle imaged by magnetic force microscopy in zero field after demagnetization was observed to change from being bi-domain or multidomain (MD) to stable single domains (SD) as the lateral size and film thickness were decreased. The critical size for SD formation was found to be close to the actual lateral sizes of 100 nm×300 nm and 150 nm×450 nm for the thicknesses of 20 and 10 nm, respectively. Only in the 10 nm thick ellipses of lateral size 100 nm×300 nm, the magnetization reversal may take place through coherent rotation. For all other investigated samples, the experimental switching field is lower than what would be required for this process.