Kosse O. The influence of physical and geometrical factors on current and heat transfer in metal oxide films and heterostructures based on it

The work is dedicated to the influence of magnetic fields, thermal effects and surface characteristics of the YBCO films on their critical and resistive properties. Research methods are magnetometry, X-ray diffractometry and AFM. It was established that the spin transition characteristics depend on linkage type between complex molecules and complex mechanism of elastic stress redistribution between molecules and lattice. Magnetic analysis allows to study the magnetic field and temperature dependences of critical current density in thin epitaxial YBCO films, prepared by laser ablation on SrTiO3 single-crystal substrates. A method for determination of pinning mechanism in HTSC films is proposed. A model of vortex pinning in superconducting films by undulation on its surface is proposed. The dependence of critical current density on HTSC films thickness under low magnetic fields is measured. It could be explained by vortex pinning on stepped surface relief. Measurements of differential susceptibility of YBCO films and YBCO-STO-LCMO structures with different STO thickness were carried out. The temperature dependence of dissipative part of film response of high-temperature superconductor loaded by transport current on alternating magnetic field is measured. Thermal hysteresis of the response is discovered, and value of this hysteresis is determined by transport current.