Influences of granular microstructure on the reversal mechanism of Co nanoelements

• Published in: Journal of applied physics 2002-05, Vol.91 (10), p.6923-6925
• Main Authors: Spargo, A. W., Ridley, P. H. W., Roberts, G. W., Chantrell, R. W.
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.1452191

A two-dimensional micromagnetic simulation is developed using a spatial finite element method, with the dynamic Gilbert equations discretized by a Galerkin method. An algorithm is presented for the generation of granular microstructures via the Voronoi tessellation and rectangular nanoelements of 200×40×20 nm3 are constructed. Hysteresis simulations are performed on isolated nanoelements in order to determine the extent to which experimentally observed variations in coercivity are attributable to the microstructural properties rather than magnetostatic interactions with neighboring members of an array. Dependence of coercivity on grain size is examined, as well as the role of grain structure in the reversal process. Mean grain size is shown to dictate the mode of reversal, whereas grain irregularity is observed to influence specific intermediate magnetization configurations and therefore specific coercivity values. Low correlation between grain irregularity and coercivity indicates that the magnetization dynamics depend on a combination of physical microstructure and easy-axis distribution unique to each nanoelement.