Size and shape dependence of the magnetic ordering temperature in nanoscale magnetic particles
Article first published online: 26 OCT 2012
© 2012 The Authors Geophysical Journal International © 2012 RAS
Geophysical Journal International
Volume 191, Issue 3, pages 954–964, December 2012
How to Cite
Shcherbakov, V. P., Fabian, K., Sycheva, N. K. and McEnroe, S. A. (2012), Size and shape dependence of the magnetic ordering temperature in nanoscale magnetic particles. Geophysical Journal International, 191: 954–964. doi: 10.1111/j.1365-246X.2012.05680.x
- Issue published online: 12 NOV 2012
- Article first published online: 26 OCT 2012
- Accepted 2012 September 17. Received 2012 August 14; in original form 2012 May 25
- Biogenic magnetic minerals;
- Environmental magnetism;
- Magnetic and electrical properties;
- Magnetic mineralogy and petrology;
- Rock and mineral magnetism.
Natural rocks and synthetic analogues can contain extremely small scaled magnetic minerals varying in shape from approximately equidimensional nanoparticles to lower dimensionally shaped lamellae resembling thin films or whiskers.
The magnetic ordering temperatures of such nanomagnetic structures can significantly depend on their size and shape. Here, a general method for detailed numerical or analytical calculations of these ordering temperatures is developed. Based on a modified mean-field approach, the result proves a refined version of a known scaling law that links atomic-layer number to the Curie temperatures of nanostructures. An analytic expression for the dependence of the Curie temperature on the atomic-layer number is obtained for thin films and rectangular nanostructures. It is confirmed by comparison to experimental results.