Micromagnetic simulator for complex granular systems based on Voronoi tessellation

• Published in: Journal of magnetism and magnetic materials Vol. 482; pp. 350 - 357
• Main Authors: Menarini, Marco, Lubarda, Marko V., Chang, Ruinan, Li, Shaojing, Fu, Sidi, Livshitz, Boris, Lomakin, Vitaliy
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.07.2019; Elsevier BV
• Subjects: Algorithms; Computer simulation; Domain wall; Domain walls; Fast Fourier transformations; Fourier transforms; GPU-accelerated; Granular materials; Granular media; Granular structure; Graphics processing units; Interfacial properties; Magnetic recording; Magnetization reversal; Micromagnetic; Microstructure; Multilayers; Nanowires; Read heads; Simulations; Tape recording; Tessellation; Voronoi; Voronoi graphs; Simulations; GPU-accelerated; Micromagnetic; Domain wall; Voronoi; Granular structure
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2019.03.021

•Micromagnetic code based on Voronoi tessellation.•Magnetostatic field computed using a non-uniform fast Fourier method augmented with exact near field computation.•Exchange field computed on Voronoi geometry.•GPU accelerated computation.•Used to simulate SNR and Domain Wall Motion in granular recording media. A micromagnetic code based on Voronoi tessellation and the non-uniform fast Fourier transform (NUFFT) method is presented. The code is capable of efficiently and accurately simulating magnetization dynamics in large and structurally complex granular systems, such as multilayer granular media used for perpendicular magnetic recording, bit patterned media, granular nanowires, and read heads. In these systems the granular microstructure and distributions in grain and interface properties play an important role in device performance. The presented Voronoi simulator allows comprehensive studies to be performed as it accounts for the detailed granular microstructure and distributions that characterize true systems. Simulation time is greatly reduced by a non-uniform fast Fourier transform algorithm and implementation on graphics processing units (GPUs). Simulations of conventional magnetic recording, heat-assisted magnetization reversal, domain wall dynamics in granular nanowires, and particulate tape recording are presented.