Nanocomposites and nanomaterials 

Investigation of the percolation threshold of electrical properties in YSZ – nanopowder systems 
Gridina E.A.1, 2, Doroshkevich A.S.2, 3, Lyubchyk A.I.4, Shylo A.V.3, Islamov A.Kh.2, Nicoleta Cornei5, Carmen Mita2,5,  D.M.Mardare5

1 Dubna International University, 141980, st. Universitetskay, 19, Dubna, Russia
E-mail: gridina.lisa@mail.ru
2 Joint Institute for Nuclear Research, 141980, str. Joliot-Curie, 6, Dubna, Russia.
3 Donetsk Institute for Physics and Engineering named after O O Galkin NAS of Ukraine, 03680, Nauki ave, 46, Kyiv, Ukraine.
4i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, New University of Lisbon  and CEMOP/UNINOVA, Caparica, Portugal
5Alexandru Ioan Cuza University of Iasi, Faculty of Physics, Romania 

The features of hydrated nanopowder system transition from non-conducting state to state with final conductivity are interesting for power nanoelectronics. The purpose of this work is to study the hydrated nanopowder systems of YSZ composition in strong electric field.
The powders of ZrO2 - 3% mol Y2O3 (YSZ) composition which was obtained by the method of co-precipitation followed by annealing at temperatures from 400°, 500° and 600°C were used. The laboratory models of nanopowder humidity sensors in the form of polymer films filled with nanosized YSZ crystallites were obtained by applying a powder slurry in 4% PVA solution in water to dielectric substrates with silver electrodes. The distance between the electrodes was 2 mm. The dependence of electrical resistance to humidity at the samples was recorded by using a universal measuring device VC9808 in voltage range up to 1000V. Humidity was controlled by using of the salts in the range of 60-75%.
It has been found that the process of percolation of electrical conductivity in YSZ systems with particle size of 7.5nm (annealing at 400oC) in the electric field up to 400V/mm has an extreme non-monotonic character. It has been found that the feature is reduced by increasing particle size. 

This study was performed in the scope of the H2020/MSCA/RISE/SSHARE number 871284 project and the Grant of «Development of functional environments of submicroscopic solid-state media for ultrahigh-density electric energy capacitors based on Zirconia nanopowders for nanoelectronics and microsystem technology» of JINR - Romania 2020.