Co nanostructures in ordered templates: comparative FORC analysis

• Published in: Nanotechnology 2013-11, Vol.24 (47), p.475703-10
• Main Authors: Proenca, M P, Merazzo, K J, Vivas, L G, Leitao, D C, Sousa, C T, Ventura, J, Araujo, J P, Vazquez, M
• Format: Article
• Language: English
• Subjects: Arrays; Chemical synthesis methods; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Devices; Elongation; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Magnetic properties and materials; Magnetic properties of nanostructures; Materials science; Methods of nanofabrication; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Nanostructure; Nanotubes; Nanowires; Physics; Porosity; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Tuning
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/24/47/475703

A comparative study on the structural and magnetic properties of highly ordered hexagonal arrays of Co nanoholes, nanowires, nanopillars and nanotubes, with tuned pore/wire/tube diameters, is here presented. The magnetic interactions and their dependence on the geometric features of the arrays were studied using first-order reversal curves (FORCs). For all nanostructures we observe an increase of the magnetostatic interactions with the templates' pore diameter, with the higher (smaller) values found for the nanowire (nanohole) arrays. For the smallest diameters studied (35 nm), all types of arrays could be considered as almost isolated nanostructures, where local interactions prevail. In particular, both nanotube and nanohole arrays exhibit considerable local magnetostatic interactions coming from the stray fields within each void or empty core. On the other hand, the coercivity is found to decrease with diameter for the elongated nanostructures, while it increases with the pore diameter for the nanohole arrays. This behavior is associated with the magnetization reversal mechanisms present in each array. This work highlights a versatile route to tailor the size, geometrical arrangement and magnetostatic interactions of ordered arrays and demonstrates their importance for the tuning of the magnetic behavior of nanometric devices.