Electronic, Magnetic and Spectroscopic Properties of Vanadium, Chromium and Manganese Nanostructures

Abstract

This chapter presents some aspects of the electronic, magnetic and spectroscopic properties of vanadium, chromium and manganese aggregates deposited on substrates or embedded in a host, mainly metallic. Those elements present a sizeable magnetic moment in their atomic form and non-ferromagnetic behaviour for the corresponding bulk materials. More precisely, vanadium, except in the atomic form and for very small cluster sizes (free or embedded), is magnetically dead. It presents a sizeable moment when in contact with strong ferromagnets like Fe, Co or Ni. Chromium presents, in the bulk form, a competition between classical anti-ferromagnetic behaviour and spin density wave (SDW). Those various behaviours are energetically almost degenerate in energy so that they can be both present. However, when the dimension shrinks, the SDW configuration does not survive. Moreover, when Cr atoms are in contact with Fe, Co or Ni a competition between the intrinsic non-ferromagnetic behaviour of Cr and the induced ferromagnetic polarization arising from the strong ferromagnet leads to complicated magnetic maps. Also the magnetic behaviour of manganese is non-trivial. The bulk magnetic behaviour is of complex anti-ferromagnetic type with some kind of non-collinear behaviour. Ferromagnetic behaviour of Mn aggregates generally seems unlikely, but a few Mn atoms may acquire a somewhat ferromagnetic configuration. However, without a constraint of collinearity, those Mn atoms follow non-collinear behaviour.