The low-temperature electric conductivity of YBaCuO and LaSrMnO dielectricfilms obtained by a pulsed laser sputter deposition technique

We have studied the electric conductivity of YBaCuO and LaSrMnO dielectric films obtained by pulsed laser sputtering of targets possessing metallic co nductivity. The plots of the sample resistance versus temperature R = R(T) measured at T < T-cr (T-cr = 160-240 K) exhibit regions where R is independ ent of the temperature. This phenomenon is probably related to manifestatio ns of the quantum confinement effects upon the conversion of small grains i nto quantum dots. In the region of T < T-cr , the electric conductivity of the system is determined by a mechanism of the phononless electron tunnelin g with participation of the atomic-type states belonging to small grains (c lusters) featuring metallic conductivity in the amorphous matrix. (C) 2000 MAIK "Nauka/Interperiodica".