Limitations of the macrospin approximation of materials with inhomogeneous perpendicular anisotropy
Abstract
Experimental investigations of the perpendicular anisotropy in thin films that are interpreted using a macrospin model often require the inclusion of a higher-order anisotropy contribution. However, recent ferromagnetic resonance experiments on [Co/Ni]N multilayers indicate that the macrospin model cannot explain the full angular dependence in this system. Using micromagnetic simulations of a system with lateral variations of the second-order perpendicular uniaxial anisotropy, we show that while the macrospin model is able to capture the average properties of the system along high symmetry orientations by including a higher-order anisotropy, the model fails to reproduce the full angle dependence. Our studies provide another indication that higher-order anisotropies may not be intrinsic to these systems but instead may be caused by inhomogeneities.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 21, 2020
- Source ID
- 10.1063/5.0022074
Entities
People
- Anish Rai
- Arjun Sapkota
- Ashok Pokhrel
- Claudia Mewes
- Derek Lau
- Jamileh Beik Mohammadi
- Marc Degraef
- Maxwell P Li
- Tim Mewes
- Vincent Sokalski
Organizations
- Carnegie Mellon University
- Defense Advanced Research Projects Agency
- Loyola University New Orleans
- National Science Foundation
- University of Alabama