Synthesis and superconductivity of organometallic fullerides M(3–n)(NR4)(n)C60, where M = K, Rb; R = H, D, Me, Et, Bu; n = 1, 2,
V. A. Kulbachinskii, N. S. Ezhikov, R. A. Lunin, and B. M. Bulychev
M. V. Lomonosov Moscow State University, Low Temperature Physics and Superconductivity Department119991, GSP-1, Moscow, Russia
Received September 9, 2020, published online November 24, 2020
We present experimental data on the synthesis and investigation of the superconducting and structural proper-ties of organometallic fullerides M(3–n)(NR4)(n)C60, where M = K, Rb; R = hydrogen H, deuterium D, methyl Me, ethyl Et, butyl Bu; n = 1, 2, 3, synthesized by exchange reactions of homofullerides of alkali metals of composition K3C60 and Rb3C60 with ammonium halides in the medium of absolute toluene or tetrahydrofuran (THF) at temperatures from 23 °С to 110 °С. We have studied also superconductivity in Rb2NH4C60 and Rb2ND4C60 samples with replacement of hydrogen for deuterium in ammonium, as well as in K2NH4C60 and K2ND4C60. The superconducting transition temperature did not change with replacement H by D within the measurement accuracy.
Key words: isotope effect, organometallic fullerides, superconducting and structural properties.