Transition metal nitrides superconductivity

The phenomenon of superconductivity is common for all fee transition metal nitrides of groups 4 and 5 and is also observed in fee MoNi- and hexagonal MoN. 5-NbNi x... 

Figure 12 Superconducting transition on temperatures (normalized relative to maximmn Tg) as a function of stoichiometry for various transition metal nitrides. For 5-H fNi j , different functions have been reported (a,h). (Ref. 64. Reproduced by permission of Wiley)...

There also exist structural similarities between the MeN clusters and the class of solid-state compounds known as transition metal nitrides. In these refractory compounds the nitrogen exists in either an octahedral or a trigonal prismatic array of transition metals 125). The interest in using transition metal nitrides for superconducting thin films as well as chemically inert coatings (i25) should promote studies in which nitrido clusters could be used as starting materials for the synthesis of new refractory materials. 

A mixture of metallic, covalent and ionic components prevails in the bonding of transition metal carbides, nitrides, and carbonitrides. The metallic character is shown by the high electrical conductivities of these compounds. The bonding mechanism has been described extensively by a variety of approaches for calculating the density of states (DOS) and hence the electron density in f.c.c. transition metal carbides, nitrides, and oxides [11]. In the DOS of these compounds there is a minimum at a valence electron concentration (VEC) of 8, which corresponds to the stoichiometric composition of the group ivb carbides TiC, ZrC, and HfC. Transition metal carbides have a lower DOS at the Fermi level than the corresponding transition metal nitrides, hence the electrical properties such as electrical and thermal conductivity and the superconducting transition temperature, T, are lower than those of the nitrides. 

Superconductivity is common among all f.c.c. transition metal nitrides of the IVB and VB groups as well as yMoNi f and 5MoN. 6NbN < shows the highest... 

Alleno, E P. Berger, E. Leroy and C. Godart, 2001, in Rare Earth Transition Metal Borocarbides (Nitrides) Superconducting, Magnetic and Normal State Properties, eds K.-H. Muller and V.N. Narozh-nyi (Kluwer Acad. Publ., Dordrecht) p. 265. 

Cava, R.J., 2001, in Rare Earth Transition Metal Borocarbides (Nitrides) Superconducting, Magnetic and... 

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