R&D: Emergence of Magnetic Transition in Cobalt Oxide Nanowires on Vicinal Pt Substrate

IEEE Magnetics Letters has published an article written by Kseniya Mikhailovna Tsysar, Physical, Lomonosov Moscow State University, 64935 Moskva, Russian Federation, 119991, Yaroslav Koshelev, Skolkovo Institute of Science and Technology, 366033 Skolkovo, Moskovska, Russian Federation, Dmitry Bazhanov, and Ekaterina Smelova, Moscow, Russian Federation.

Abstract: “The main task of spintronics in the development of new storage devices and new data transmission technologies is to create a method for effective control of the magnetic properties of nanoobjects. For the development of magnetic memory devices, it is necessary to search new low-dimensional systems with several magnetic phases. One-dimensional wires made of magnetic metal oxides using magneto-optics technology can serve as a promising basis for such devices. Our work is devoted to the theoretical study of the magnetic properties of supported pure and oxidized Co nanowires (NW) on the vicinal surface of Pt substrate. The main goal of our work is to study the influence of oxygen on magnetic properties of Co NW. Transition metal atoms are magnetic, and oxygen effectively interacts with electromagnetic (EM) radiation in the optical range. Thus, by choosing the resonant frequency, it becomes possible to change the magnetic properties of oxide NW as a whole and switch the magnetic state of the wire by using EM field. Our study has shown that Co oxide (CoO) nanowires can exhibit magnetic properties in ground state. Moreover, we observed the emergence of magnetic transition from ferromagnetic (FM) to antiferromagnetic (AFM) state in a CoO nanowire under surface oxidation. We have shown that the magnetic properties of oxidized nanowires depend strongly on the surface geometry. The study of the electronic structure of CoO nanowires has explained the reason of formation of several magnetic states in them. The analysis of band structures of pure and oxidized Co nanowire has shown that changes of magnetic states can be explained by the changes of band structure due to oxidation. Moreover, we have shown that the oxidation decreases the value of magnetic moments of the Co atoms in compare to pure nanowire, however the values of these moments are still high enough.“