Studies of YBa2Cu3O6+x degradation and surface conductivity properties by Scanning Spreading Resistance Microscopy

Martin Truchly; Tomas Plecenik; Ondrej Krsko; Maros Gregor; Leonid Satrapinsky; Tomas Roch; Branislav Grancic; Marian Mikula; Agata Dujavova; Stefan Chromik; Peter Kus; Andrej Plecenik

doi:10.1016/j.physc.2012.07.004

arXiv · 1301.0397

Studies of YBa2Cu3O6+x degradation and surface conductivity properties by Scanning Spreading Resistance Microscopy

Martin Truchly·Tomas Plecenik·Ondrej Krsko·Maros Gregor·Leonid Satrapinsky·Tomas Roch·Branislav Grancic·Marian Mikula·Agata Dujavova·Stefan Chromik·Peter Kus·Andrej Plecenik

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Abstract

Local surface conductivity properties and surface degradation of c-axis oriented YBa2Cu3O6+x (YBCO) thin films were studied by Scanning Spreading Resistance Microscopy (SSRM). For the surface degradation studies, the YBCO surface was cleaned by ion beam etching and the SSRM surface conductivity map has been subsequently repeatedly measured over several hours in air and pure nitrogen. Average surface conductivity of the scanned area was gradually decreasing over time in both cases, faster in air. This was explained by oxygen out-diffusion in both cases and chemical reactions with water vapor in air. The obtained surface conductivity images also revealed its high inhomogenity on micrometer and nanometer scale with numerous regions of highly enhanced conductivity compared to the surroundings. Furthermore, it has been shown that the size of these conductive regions considerably depends on the applied voltage. We propose that such inhomogeneous surface conductivity is most likely caused by varying thickness of degraded YBCO surface layer as well as varying oxygen concentration (x parameter) within this layer, what was confirmed by scanning Auger electron microscopy (SAM). In our opinion the presented findings might be important for analysis of current-voltage and differential characteristics measured on classical planar junctions on YBCO as well as other perovskites.

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Martin Truchly, Tomas Plecenik, Ondrej Krsko, Maros Gregor, Leonid Satrapinsky, Tomas Roch, Branislav Grancic, Marian Mikula, Agata Dujavova, Stefan Chromik, Peter Kus, Andrej Plecenik. 2013-01-03. Studies of YBa2Cu3O6+x degradation and surface conductivity properties by Scanning Spreading Resistance Microscopy. https://doi.org/10.1016/j.physc.2012.07.004

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