Eur. Phys. J. D (2016) 70: 137
https://doi.org/10.1140/epjd/e2016-70162-1

Regular Article

Structural and oxidation properties of CoNi nanowires

¹ Instituto de Física, Universidad Autonoma de San Luis Potosi, Alvaro Obregón 64, 78000 San Luis Potosí, S.L.P., Mexico
² Departamento de Ciencias Físicas, Universidad de La Frontera, Temuco, Chile
³ Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile

^a e-mail: jmmc@dec1.ifisica.uaslp.mx

Received: 4 March 2016
Published online: 16 June 2016

Abstract

Nanocylinders made out of CoNi alloys offer interesting properties which are dependent on the proportion of the constituent elements, the preparation methods and the thermal history of the sample. In the present paper we calculate the structural and electronic properties of Co_1−xNi_x alloys at subnanoscopic level. SIESTA program is used to relax the structures following standard protocols. Relative positions of the minority atoms (Ni) are varied aiming to find the lowest energy configurations. It is found that Ni atoms minimize energy at surface positions mainly at the ends of the cylinders. The implications of this result in the magnetic properties of the systems are discussed. The work is continued to study the oxidation properties of the different possible surface compositions. It is found that surfaces of Ni are more resistant to oxidation than Co ones. The combination of the two previous results can lead to cylinders with high magnetic coercivity and relatively high resistance to oxidation.