  Measurements of thermal excitations of V-O and Y-Ba-Cu-O solid solutions have
been performed by a method of inelastic neutron scattering for low-energy
transfers range. Features at energy transfer about 3meV and about 5meV for V-O
and Y-Ba-Cu-O accordingly were observed in neutron scattering spectra. The
reason of appearance of the observed low-energy excitations are the formation
of an effective potential of oxygen with broad weakly upwards bottom at the xy
plane of tetragonal symmetry octahedron, which the interstitial atom occupies.
The experimental observed features can be understood in the representation of
hindered quantum gyration of the interstitial atom. It was assumed that O1 and
O4 atoms in Y-Ba-Cu-O, as well as in V-O system, are in two-dimensional
quantum-well, which has almost flat bottom formed by the surrounding atoms Cu
and Ba. The possibility of formation of collective excitations of gyration-type
as a result of exchange interaction of light atoms in matrix lattice is
considered. The assumption is made that the existence of gyration-like
excitations can play an important role for explanation of some phenomena in
solid state physics, in particular in realization of high values of
temperatures of superconducting transitions in high temperature
superconductors.
