Transport Properties of Ferromagnet/Superconductor and Superparamagnet/Superconductor Heterostructures Based on Ni/YBCO

Abstract

The article presents a study of the transport properties of high-temperature superconducting compounds of the Y-Ba-Cu-O system with the addition of the carbon nanomaterial (carbon nanotubes) "Taunite" in different concentrations. According to the data of X-ray phase analysis, scanning electron microscopy and magnetic measurements, it was determined that the carbon nanotube "Taunite" contains ferro-and superparamagnetic particles (~ 30 nm). The dependences of the resistance of the samples on the temperature have been constructed, and the temperature of the transition of the samples to the superconducting state (~ 90 K) has been determined, and the features ("stages") on the resistance curves are observed below. Nickel nanoparticles in the carbon nanotubes "Taunite" have been established to not affect the critical temperature of the superconducting transition, yet after reaching a certain concentration, they destroy the superconducting state.