Using ellipsometry with lock-in detection to measure activation energy of ion diffusion in ionic and mixed conductors

Guy Lazovski, Ellen Wachtel, Yoed Tsur, Igor Lubomirsky

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We describe a technique for measuring the activation energy of ion diffusion in ionic and mixed ionic/electronic conductors. The technique is based on monitoring small changes in refractive index near the interface of a semitransparent gold electrode with the sample surface. Constant bias voltage is applied to the sample to weakly perturb the distribution of charge carriers near this front electrode. The relaxation process induced by bias removal is probed by applying alternating voltage and monitoring by ellipsometry with lock-in detection the changes in the refractive index dominated by changes in material polarizability. Since the ionic contribution to the total material polarizability is much larger than that of electrons or protons, the diffusion of ions can be distinguished. Measurements were made as a function of temperature on single crystals of 8 mol% Y-stabilized zirconia (YSZ8), on ceramic pellets of 20 mol% Gd doped CeO2 (GDC20) and on single crystals of 0.03 mol% Fe-doped SrTiO3 (Fe-STO). In YSZ8, a single moving species (oxygen vacancies) with activation energy of 0.8 eV was detected. The "wet" and "dry" states of GDC20 can be clearly distinguished: in the "wet" state there are mobile species other than oxygen vacancies, most likely protons. In Fe-doped SrTiO3, the proposed technique can reliably measure the activation energy of oxygen ion diffusion on a background of the much larger electronic conductivity.

Original languageEnglish
Pages (from-to)7-16
Number of pages10
JournalSolid State Ionics
Volume264
DOIs
Publication statusPublished - Oct 15 2014

Fingerprint

Ellipsometry
ellipsometry
conductors
Activation energy
Oxygen vacancies
Ions
activation energy
Protons
Refractive index
Single crystals
refractivity
ions
Electrodes
electrodes
protons
Monitoring
single crystals
electric potential
Relaxation processes
oxygen

Keywords

  • Ellipsometry
  • Impedance spectroscopy
  • Oxygen ion conductivity

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Chemistry(all)

Cite this

Using ellipsometry with lock-in detection to measure activation energy of ion diffusion in ionic and mixed conductors. / Lazovski, Guy; Wachtel, Ellen; Tsur, Yoed; Lubomirsky, Igor.

In: Solid State Ionics, Vol. 264, 15.10.2014, p. 7-16.

Research output: Contribution to journalArticle

@article{4b8882f921854adb81f8f21da16d29d4,
title = "Using ellipsometry with lock-in detection to measure activation energy of ion diffusion in ionic and mixed conductors",
abstract = "We describe a technique for measuring the activation energy of ion diffusion in ionic and mixed ionic/electronic conductors. The technique is based on monitoring small changes in refractive index near the interface of a semitransparent gold electrode with the sample surface. Constant bias voltage is applied to the sample to weakly perturb the distribution of charge carriers near this front electrode. The relaxation process induced by bias removal is probed by applying alternating voltage and monitoring by ellipsometry with lock-in detection the changes in the refractive index dominated by changes in material polarizability. Since the ionic contribution to the total material polarizability is much larger than that of electrons or protons, the diffusion of ions can be distinguished. Measurements were made as a function of temperature on single crystals of 8 mol{\%} Y-stabilized zirconia (YSZ8), on ceramic pellets of 20 mol{\%} Gd doped CeO2 (GDC20) and on single crystals of 0.03 mol{\%} Fe-doped SrTiO3 (Fe-STO). In YSZ8, a single moving species (oxygen vacancies) with activation energy of 0.8 eV was detected. The {"}wet{"} and {"}dry{"} states of GDC20 can be clearly distinguished: in the {"}wet{"} state there are mobile species other than oxygen vacancies, most likely protons. In Fe-doped SrTiO3, the proposed technique can reliably measure the activation energy of oxygen ion diffusion on a background of the much larger electronic conductivity.",
keywords = "Ellipsometry, Impedance spectroscopy, Oxygen ion conductivity",
author = "Guy Lazovski and Ellen Wachtel and Yoed Tsur and Igor Lubomirsky",
year = "2014",
month = "10",
day = "15",
doi = "10.1016/j.ssi.2014.06.015",
language = "English",
volume = "264",
pages = "7--16",
journal = "Solid State Ionics",
issn = "0167-2738",
publisher = "Elsevier",

}

TY - JOUR

T1 - Using ellipsometry with lock-in detection to measure activation energy of ion diffusion in ionic and mixed conductors

AU - Lazovski, Guy

AU - Wachtel, Ellen

AU - Tsur, Yoed

AU - Lubomirsky, Igor

PY - 2014/10/15

Y1 - 2014/10/15

N2 - We describe a technique for measuring the activation energy of ion diffusion in ionic and mixed ionic/electronic conductors. The technique is based on monitoring small changes in refractive index near the interface of a semitransparent gold electrode with the sample surface. Constant bias voltage is applied to the sample to weakly perturb the distribution of charge carriers near this front electrode. The relaxation process induced by bias removal is probed by applying alternating voltage and monitoring by ellipsometry with lock-in detection the changes in the refractive index dominated by changes in material polarizability. Since the ionic contribution to the total material polarizability is much larger than that of electrons or protons, the diffusion of ions can be distinguished. Measurements were made as a function of temperature on single crystals of 8 mol% Y-stabilized zirconia (YSZ8), on ceramic pellets of 20 mol% Gd doped CeO2 (GDC20) and on single crystals of 0.03 mol% Fe-doped SrTiO3 (Fe-STO). In YSZ8, a single moving species (oxygen vacancies) with activation energy of 0.8 eV was detected. The "wet" and "dry" states of GDC20 can be clearly distinguished: in the "wet" state there are mobile species other than oxygen vacancies, most likely protons. In Fe-doped SrTiO3, the proposed technique can reliably measure the activation energy of oxygen ion diffusion on a background of the much larger electronic conductivity.

AB - We describe a technique for measuring the activation energy of ion diffusion in ionic and mixed ionic/electronic conductors. The technique is based on monitoring small changes in refractive index near the interface of a semitransparent gold electrode with the sample surface. Constant bias voltage is applied to the sample to weakly perturb the distribution of charge carriers near this front electrode. The relaxation process induced by bias removal is probed by applying alternating voltage and monitoring by ellipsometry with lock-in detection the changes in the refractive index dominated by changes in material polarizability. Since the ionic contribution to the total material polarizability is much larger than that of electrons or protons, the diffusion of ions can be distinguished. Measurements were made as a function of temperature on single crystals of 8 mol% Y-stabilized zirconia (YSZ8), on ceramic pellets of 20 mol% Gd doped CeO2 (GDC20) and on single crystals of 0.03 mol% Fe-doped SrTiO3 (Fe-STO). In YSZ8, a single moving species (oxygen vacancies) with activation energy of 0.8 eV was detected. The "wet" and "dry" states of GDC20 can be clearly distinguished: in the "wet" state there are mobile species other than oxygen vacancies, most likely protons. In Fe-doped SrTiO3, the proposed technique can reliably measure the activation energy of oxygen ion diffusion on a background of the much larger electronic conductivity.

KW - Ellipsometry

KW - Impedance spectroscopy

KW - Oxygen ion conductivity

UR - http://www.scopus.com/inward/record.url?scp=84904203584&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84904203584&partnerID=8YFLogxK

U2 - 10.1016/j.ssi.2014.06.015

DO - 10.1016/j.ssi.2014.06.015

M3 - Article

VL - 264

SP - 7

EP - 16

JO - Solid State Ionics

JF - Solid State Ionics

SN - 0167-2738

ER -