Systematic study of magnetization reversal in square Fe nanodots of varying dimensions in different orientations
- 37 Downloads
Ferromagnetic nanoparticles can be used for data storage, spintronics, and other applications. Especially vortex states are often suggested to be used to store information. Due to the shape anisotropy dominating in nanoparticles, magnetization reversal processes can be expected to depend not only on the dimensions, but also on the orientation with respect to the external magnetic field. While several papers evaluate magnetization dynamics, including vortex precessions, in round nanodots, square nanodots are less often investigated. Here we report on different magnetization reversal processes found in micromagnetic simulations of square Fe nanodots with lateral dimensions between 100 nm and 500 nm and thicknesses between 10 nm and 50 nm. Choosing magnetic field orientations parallel to one of the square edges and under 45∘, seven different reversal mechanisms were found, most of them including a single-vortex state, while in some cases two, three or more vortex-antivortex pairs were found. The ground state, i.e. the magnetic state at vanishing external magnetic field, was often a single-vortex state, making the nanodot with the respective dimensions suitable for data storage applications. The stability of this state, i.e. the field range over which it existed, depended strongly on the lateral dimensions and the dot thickness and was largest for small lateral dimensions and large thicknesses.
KeywordsMagnetic nanodots Micromagnetic simulation Magnetization reversal Vortex Antivortex
This work was supported by Volkswagen Foundation grant “Adaptive Computing with Electrospun Nanofiber Networks” no. 93679, by the SUT Rector Grant 14/990/RGJ18/0099 as well as the internal SUT project BK-229/RIF/2017.
- 4.Romero, M., Pardo, H., Faccio, R., Suescun, L., Vazquez, S., Laborda, I., Fernandez-Werner, L., Acosta, A., Castiglioni, J., Mombru, A.W.: A Study on the polymer precursor formation and microstructure evolution of square-shaped (La0.5Ba0.5)(Mn0.5Fe0.5)O3 ceramic nanoparticles. J. Ceramic Sci. Tech. 6, 221–230 (2015)Google Scholar
- 16.Donahue, M.J., Porter, D.G.: OOMMF User’s Guide, Version 1.0 Interagency Report NISTIR 6376. National Institute of Standards and Technology, Gaithersburg (1999)Google Scholar
- 19.Lemcke, O.: Thetaevolve module for OOMMF. available: http://www.nanoscience.de/groupr/stm-spstm/projects/temperature/download.shtml (2002)
- 20.Ehrmann, A., Blachowicz, T.: Vortex and double-vortex nucleation during magnetization reversal in Fe nanodots of different dimensions, J. Magn. Magn. Mater., submittedGoogle Scholar