Simulations of FMR for study the shape anisotropy in square hollow nanopillars

• Published in: Journal of magnetism and magnetic materials 2022-02, Vol.544, p.168642, Article 168642
• Main Authors: da Silva, J.F.O., Guerra, Y., Padrón-Hernández, E.
• Format: Article
• Language: English
• Subjects: Anisotropy; Dipole interactions; Ferromagnetic resonance; Ferromagnetism; Micromagnetic simulation; Nanopillars; Self-demagnetizing field, FMR
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2021.168642

•Analysis about the geometry dependence of anisotropy field in hollow nanopillars.•A primary abortion peak was detected by the FFT from de m(t) signal.•A secondary FMR peak was detected and associated to edges effects. A study of ferromagnetic resonance in square hollow nanopillars was carried out, with the aim of analyzing the effects of geometry. Nanopillars (NPs) with L = 120 nm length and D = 30 nm external width were studied. By fitting the data for parallel field and using the Primary peak, the anisotropy field was HA = 97.2, 116.4 and 144.5 kA/m for d = 0, 10 and 20 nm, respectively. For perpendicular field, HA = 175, 193 and 251 kA/m for d = 0, 10 and 20 nm, respectively. The variations were attributed to the increase in dipole interactions, as the cavity size increases. A secondary peak was also fitted and HA = 222.5, 220 and 226.9 kA/m were obtained for parallel configuration. Thus, this secondary peak, from regions whose local field varies little with the dimensions of the cavity, were attributed to the effects of parallel edges.