Properties of percolation channels in planar memristive structures based on epitaxial films of a YBa₂Cu₃O_7−δ high temperature superconductor

Abstract

The transport properties of the percolation channels of memristive structures based on YBa2Cu3O7−δ epitaxial films were studied. Molecular electronics and Andreev reflection spectroscopy were utilised, and the influence of the superconductive transition of electrodes on resistive switching effects in these structures was examined. Based on the analysis of the conductivity mechanisms in the obtained heterostructures, it is assumed that percolation channels form through a chain of domains disordered by oxygen about 10 nm in diameter, with a maximum Tc of 60 K. Zero-bias anomalies of the dynamic resistance of the studied structures display temperature dependence of the critical current of typical superconductor—normal—superconductor weak links within the framework of Kulik–Omel’yanchuk theory in the dirty limit. A simulation was used to determine the physical parameters of the studied heterostructures.

Electrical conduction mechanisms of metal / high-T c superconductor (YBCO) interfaces

“…Indeed, metal / YBCO devices have shown interesting bipolar resistive switching properties [8][9][10][11][12], with particular relaxation effects [7,13], the electrochemical control of YBCO's carrier density [14] and present some particular characteristics proper of inhomogeneous interfaces. [6,[15][16][17][18][19].…”

“…Instead, their interest is based in their capacity to shed light on the electrical transport mechanisms through a metal-complex oxide interface, which is a common feature of many memristive interfaces and particularly to improve our knowledge of the electrical transport and dielectric properties of YBCO. Indeed, metal/YBCO devices have shown interesting bipolar resistive switching properties [8][9][10][11][12], with particular relaxation effects [7,13], the electrochemical control of YBCO's carrier density [14] and present some particular characteristics proper of inhomogeneous interfaces [6,[15][16][17][18][19].…”

Proton irradiation effects on metal-YBCO interfaces

“…What makes YBCO such an interesting material to build ReRAM devices is the possibility of modifying its oxygen content by applying moderate electric fields and thus producing large changes in its conductivity [17][18][19]. As will be discussed in detail later, transport properties through metal-YBCO interfaces are controlled by oxygen content inhomogeneities of YBCO, close to the interface [20][21][22][23][24][25][26].…”