Magnetization switching in nanoscale ferromagnetic grains: description by a kinetic Ising model

• Published in: Journal of magnetism and magnetic materials 1995-09, Vol.150 (1), p.37-50
• Main Authors: Richards, Howard L., Sides, Scott W., Novotny, M.A., Rikvold, Per Arne
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Domain effects, magnetization curves, and hysteresis; Exact sciences and technology; Magnetic properties and materials; Magnetization curves, hysteresis, Barkhausen and related effects; Magnetization curves, magnetization reversal, hysteresis, barkhausen and related effects; Metals. Metallurgy; Physics
• ISSN: 0304-8853
• DOI: 10.1016/0304-8853(95)00402-5

The magnetic relaxation of ferromagnetic powders has been studied for many years, largely due to its importance to recording technologies. However, only recently have experiments been performed that resolve the magnetic state of individual sub-micron particles. Motivated by these experimental developments, we use droplet theory and Monte Carlo simulations to study the time and field dependence of some quantities that can be observed by magnetic force microscopy. Particular emphasis is placed on the effects of finite particle size. The qualitative agreement between experiments on switching and our simulations in individual single-domain ferromagnets suggests that the switching mechanism in such particles may involve local nucleation and subsequent growth of droplets of the stable phase.