4.7 Article

A tool to predict coercivity in magnetic materials

Journal

ACTA MATERIALIA
Volume 208, Issue -, Pages -

Publisher

PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.actamat.2021.116697

Keywords

Micromagnetics; Coercivity; Nucleation barrier; Magnetostriction

Funding

  1. NSF [DMREF-1629026]
  2. ONR [N00014-18-1-2766]
  3. Vannevar Bush Faculty Fellowship
  4. Provost Assistant Professor Fellowship

Ask authors/readers for more resources

This study develops a theoretical and computational tool to investigate the interplay between material constants that govern coercivity in bulk magnetic alloys. The interactions between local instabilities and material constants, such as anisotropy and magnetostriction constants, are identified as key factors in governing magnetic coercivity. The study provides a theoretical framework to potentially discover novel magnetic materials with low coercivity.
Magnetic coercivity is often viewed to be lower in alloys with negligible (or zero) values of the anisotropy constant. However, this explains little about the dramatic drop in coercivity in FeNi alloys at a non-zero anisotropy value. Here, we develop a theoretical and computational tool to investigate the fundamental interplay between material constants that govern coercivity in bulk magnetic alloys. The two distinguishing features of our coercivity tool are that: (a) we introduce a large localized disturbance, such as a spike-like magnetic domain, that provides a nucleation barrier for magnetization reversal; and (b) we account for magneto-elastic energy-however small-in addition to the anisotropy and magnetostatic energy terms. We apply this coercivity tool to show that the interactions between local instabilities and material constants, such as anisotropy and magnetostriction constants, are key factors that govern magnetic coercivity in bulk alloys. Using our model, we show that coercivity is minimum at the permalloy composition (Fe21.5Ni78.5) at which the alloy's anisotropy constant is not zero. We systematically vary the values of the anisotropy and magnetostriction constants, around the permalloy composition, and identify new combinations of material constants at which coercivity is small. More broadly, our coercivity tool provides a theoretical framework to potentially discover novel magnetic materials with low coercivity. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available