Agradecimentos: This research has been funded under CONICET Grant No. PIP 11220110100720CO and UNLP Grant No. 11/X680, both from Argentina; FAPESP Grants No. 2012/04870-7 and No. 2013/13275-8 from Brazil; and MINECO projects MAT2013-48054-C2-2-R and MAT2016-76824-C3-3-R from Spain. We acknowledge...

Agradecimentos: This research has been funded under CONICET Grant No. PIP 11220110100720CO and UNLP Grant No. 11/X680, both from Argentina; FAPESP Grants No. 2012/04870-7 and No. 2013/13275-8 from Brazil; and MINECO projects MAT2013-48054-C2-2-R and MAT2016-76824-C3-3-R from Spain. We acknowledge the technical support from the Scientific-Technical Services of the University of Oviedo (SCT's) and particularly to the Laboratory of Nanoporous Membranes

Abstract: A model describing the effect of magnetic dipolar interactions on the susceptibility of magnetic nanopillars is presented. It is an extension of a recently reported model for three-dimensional randomlike dispersions of nearly spherical nanoparticles in equilibrium [Sanchez et al., Phys....

Abstract: A model describing the effect of magnetic dipolar interactions on the susceptibility of magnetic nanopillars is presented. It is an extension of a recently reported model for three-dimensional randomlike dispersions of nearly spherical nanoparticles in equilibrium [Sanchez et al., Phys. Rev. B 95, 134421 (2017)], to well-ordered arrays of nanoparticles out of equilibrium. To test it, a high-quality benchmark consisting of a two-dimensional hexagonal arrangement of quasi-identical parallel nickel nanopillars embedded in a porous alumina template was fabricated. This model is based on an effective demagnetizing tensor, which only depends on a few morphological parameters of the sample, as the nearest-neighbor distance between pillars and the volume fraction of pillars in the specimen. It allows us to obtain the nanopillar intrinsic susceptibility tensor from the magnetic response of the nanopillar ensemble. The values of the in-plane and normal-to-plane susceptibility of the sample are successfully predicted by the model. Furthermore, the model reproduces the susceptibility in the applied field direction, measured for different applied field angles. In this way, it provides a simple and accurate treatment to account for the complex magnetic effects produced by dipolar interactions

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP

2012/04870-7; 2013/13275-8

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