“…Nanoporous anodic Al 2 O 3 films, obtained by the simple and inexpensive technique for two-step anodization of high-purity Al substrates (Masuda and Fukuda, 1995;Masuda and Satoh, 1996), have attracted huge interest and have been used as templates for the synthesis of a wide range of nanomaterials (Eftekhari, 2008;Lupu, 2010;Nalwa, 2011), including ordered arrays of magnetic nanowires Vázquez et al, 2005;Prida et al, 2007;Klammer et al, 2010), nanoparticles (Gultepe et al, 2007;Badini et al, 2011), nanotubes (Imai et al, 1999;Daub et al, 2007;Zierold et al, 2011;Proença et al, 2013) arrays of antidots (Masuda and Fukuda, 1995;Vázquez et al, 2008;López-Antón et al, 2009;Béron et al, 2011;Merazzo et al, 2012). Anodization of Al consists of the anodic oxidation of an Al electrode under wellcontrolled electrochemical conditions.…”