Superconducting fullerides

Brouet V, Alloul H, Garaj S, Forro L (2004) NMR Studies of Insulating, Metallic, and Superconducting Fullerides Importance of Correlations and Jahn-Teller Distortions 109 165-199... 

Brown CM, TagaS, Gogia B, Kordatos K, Margadonna S, Prassides K, Iwasa Y, Tanigaki K, Fitch AN, Pattison P (1999) Stractural and electronic properties of the noncubic superconducting fullerides A4 Cso (A = Ba, Sr). Phys Rev Lett 83 2258-2261... 

Fig. 11 Schematic electronic phase diagram of C q compounds, showing the approximate location of the metal (superconducting)-insulator phase boundary. Open symbols are values of Tc for superconducting fullerides solid symbols indicate TN (ambient pressure) and Tc (>1 GPa) of (NH3)K3C60...

NMR Studies of Insulating, Metallic, and Superconducting Fullerides Importance of Correlations and Jahn-Teller Distortions... 

Table 12.3 summarizes many known organic superconductors [26,29] and a few other superconductors the stage-1 intercalated graphite KCs, polymeric (SN)X, and superconducting fullerides. 

There are several classes of superconducting fullerides which differ in their structure and in the number of electrons per C o, e.g. KjC q, Na2CsCgo, Ba4C6o, CajCjo etc. [19]. We review below in some detail the most extensively studied family, AjC o. 

Table 1 Published Isotope Shift Experiments on Superconducting Fullerides...

The superconducting fulleride (NH3) aK2C6o has been investigated using SQUID magnetometry and NMR in two differently doped samples. NMR relaxation measurements vahdate the interpretation of the spin susceptibility in terms of density of states and rule out the presence of strong antiferromagnetic correlations in the Fermi liquid. 

K. Prassides, J. Tomkinson, C. Christides, M.J. Rosseinsky, D.W. Murphy R.C. Haddon (1991). Nature, 354, 462-463. Vibrational spectroscopy of superconducting fulleride K3C60 by inelastic neutron scattering. 

A range of metals, alloys and metallic compounds are Type I superconductors (Table 28.1). However, to put the practical limitations of working with the materials listed in Table 28.1 (and others including the superconducting fullerides described in Section 14.4) into perspective, we must compare the values of with the boiling points of available coolants, e.g. liquid He (4.2 K), H2 (20.1 K) and N2 (77 K). The low values of limit the possible applications of these materials, and illustrate why the so-called high-temperature superconductors described below are more important than superconducting metals and alloys. 

---