Calculating thermal stability and attempt frequency of advanced recording structures without free parameters

Author(s)
Christoph Vogler, Florian Bruckner, Dieter Suess, Christoph Dellago
Abstract

Ensuring a permanent increase of magnetic storage densities is one of the main challenges in magnetic recording. Conventional approaches based on single phase grains are not suitable to achieve this goal, because their grain volume is limited due to the superparamagnetic limit. Grains with graded anisotropy are the most promising candidates to overcome this limit, providing magnetic memory bits with small volumes, low coercivity, and high thermal stability at the same time. Combining micromagnetic simulations with forward flux sampling, a computational method for rare events that has been recently applied to the magnetic nanostructures, we have determined thermal escape rates and attempt frequencies of a graded media grain and two single phase grains of the same geometry. We find that graded anisotropy can increase the thermal stability of a grain by 12 orders of magnitudes from tens of milliseconds to centuries without changing the coercive field.

Organisation(s)
Computational and Soft Matter Physics
External organisation(s)
Technische Universität Wien
Journal
Journal of Applied Physics
Volume
117
No. of pages
5
ISSN
0021-8979
DOI
https://doi.org/10.1063/1.4918902
Publication date
04-2015
Peer reviewed
Yes
Austrian Fields of Science 2012
103036 Theoretical physics, 103015 Condensed matter, 103017 Magnetism, 103029 Statistical physics
ASJC Scopus subject areas
Physics and Astronomy(all)
Portal url
https://ucris.univie.ac.at/portal/en/publications/calculating-thermal-stability-and-attempt-frequency-of-advanced-recording-structures-without-free-parameters(e594141f-0994-44f9-9c8b-7fdf75d7415b).html