Low Temperature Physics: 37, 245 (2011); https://doi.org/10.1063/1.3580512 (16 pages)
Fizika Nizkikh Temperatur: Volume 37, Number 3 (March 2011), p. 313-333    ( to contents , go back )

Superconductivity and spectroscopy of homo- and heterofullerides of alkali metals and tallium

V.A. Kulbachinskii, B.M. Bulychev, V.G. Kytin, and R.A. Lunin

Lomonosov Moscow State University, Vorob`evy gory, Moscow 119991, Russia
E-mail: kulb@mig.phys.msu.ru
pos Анотація:

Received September 24, 2010

Abstract

We have synthesized fullerides AnHgxC60 (A = K, Rb, Cs; n = 2;3; x < 1); AnTlmHgxC60 (A = K, Rb, Cs; n = 1;2; m = 0,25–2; x < 1) and NanC60 (n = 2; 3) using liquid alloys of metals with mercury(amalgams). All samples were investigated with X-ray diffraction, nuclear magnetic resonance, electron spin resonance, Raman scattering and differential scanning calorimetry. The transitions to the superconducting state were observed at temperatures Tc ranged from 16.5 to 28.2 K. In fullerides of potassium K2TlmHgxC60 the optimal proportion of thallium is found to be m = 0.5, at which Тс is maximal and is equal to 22 K. The fullerides with composition CsnTlmHgxC60 (n = 1–3; m = 1;2) are not superconductors and crystallizes in orthorhombic lattices. NanC60 (n = 2;3) fullerides are not superconductors. They have structural phase transitions when temperature goes down. K2HgxC60 is a superconductor with Tc = 22 K, whereas K3HgxC60 is not a superconductor. RbnHgxC60 (n = 2;3) have Tc = 24–25 K. CsnHgxC60 (n = 2;3) are not superconductors as well as CsnTlmHgxC60 (n = 1–3; m = 1;2). KCsTlC60 has Тс = 21,7 K.

PACS: 61.48.–c Structure of fullerenes and related hollow and planar molecular structures;
PACS: 71.30.+h Metal-insulator transitions and other electronic transitions;
PACS: 74.10.+v Superconductivity: occurrence, potential candidates.

Key words: superconductivity, fulerides, nuclear magnetic resonance, electron paramagnetic resonance, raman scattering.

Download 1153466 byte View Contents