Members

Olena Okhay

Category
Researcher
Email
olena@ua.pt
Ciência ID
951B-95CB-0118
ORCID iD
0000-0002-0885-7127

Olena Okhay graduated in Microelectronics and Semiconductor Devices by the National Technical University of Ukraine “Kyiv Polytechnic Institute”, investigating the thin films of high temperature superconductive materials prepared by pulsed lased deposition and liftoff lithography. In 2009 she received PhD degree in Materials Science & Engineering from the University of Aveiro, Portugal, studying strontium titanate-based films for tunable device applications under a personal PhD grant by Portuguese Foundation for Science and Technology (FCT). Later, Dr. Okhay won a two personal 3-years post-doctoral grants by FCT to works on “New Thin Films Solar Cells Based on Graphene Oxide Modified by Ni-Quantum Dots” (in 2012, after career break due to maternities) and “Ni doped carbon-based materials for sensor application” (in 2015) at TEMA, University of Aveiro. In 2018, she received short-time post-doc position in CICECO, University of Aveiro within “Multifunctional all-oxide nanostructures for electronic applications” project, financed by FCT, Portugal and investigated ferroelectric / thermoelectric materials. In 2018 Dr. Okhay was promoted to post-doc position within Project on Corporate R&D Cooperation entitled “SGH - SMART GREEN HOMES, financed by the Fundo Europeu de Desenvolvimento Regional (FEDER) with the goal of study of piezoelectric materials for nanopiezogenerators. Science January 2019 Dr. O. Okhay worked in TEMA, University of Aveiro as contracted Independent Researcher. She also was Guest Researcher in Technical University of Sofia for 6 months in 2025. Her work concentrated on materials for energy harvesting and storage such as thermoelectric nanogenerator and supercapacitor/batteries. In particular, she worked with nanomaterials, 1D-2D carbon-family, films/ceramics, metal oxides/hydroxide, composites with polymers, etc. Her name was mentioned in >10 national/international projects (FCT, M-ERA, HORIZON, NATO) and 3 more projects were started in 2025. Her short time projects were supported by European Cooperation in Science and Technology (COST) and European Consortium of Innovative Universities (ECIU). She participated in COST actions, FAME international networks, online/offline events as well as in training schools or workshops on different scientific thematic for the improving of her personal research potential. She was invited to be a member of several evaluation juries. In addition, she has many international collaborations resulted in publications. In total, Dr. Okhay published >55 papers and 4 book chapters (h=16 based on SCOPUS). She is Guest editor in 3 Special Issues and Reviewer in >30 International Journals. She participated in International conferences with oral presentations (12 invited/keynotes talks) and posters (>30). She is member of the organizing and scientific committee of 4 international conferences.

  • 0
    fundings
  • 0
    publications

Fundings

  • Modified Reactive Hydride Nanocomposites: A promising new solution to High-Capacity Hydrogen Storage issues for Green Hydrogen Vehicles

  • Development and characterization of composite materials based on reduced graphene oxide aerogels for advanced applications

    07/01/2024
    E-COST-GRANT-CA19118-77625df5

  • Development and electrochemical characterization of the electrode materials based on graphene

    08/01/2022
    n/a

  • Power Phoenix Battery-A Full Solid State Grid-scale Storage Solution

  • Laboratório Associado de Sistemas Inteligentes

    12/01/2025
    10.54499/LA/P/0104/2020

    https://doi.org/10.54499/LA/P/0104/2020

  • Graphene based electrodes for symmetric supercapacitors

    07/01/2019
    n//a

  • Graphene-based materials for energy harvesting and storage devices

    01/30/2025
    10.54499/DL57/2016/CP1482/CT0073

    https://doi.org/10.54499/DL57/2016/CP1482/CT0073

  • CICECO-Instituto de Materiais de Aveiro

    12/31/2019
    10.54499/LA/P/0006/2020

    https://doi.org/10.54499/LA/P/0006/2020

  • Solid-state carbon-based supercapacitors for energy storage applications

    2019
    E-COST-GRANT-CA15107- 44419

  • Ni doped carbon-based materials for sensor application

    12/31/2017
    SFRH /BPD /77704 / 2011

  • Oxide-based thermoelectrics for sensor application

  • Oxide-based thermoelectrics for sensor application

    2014
    PTDC/CTM-NAN/5488/2014

  • New thin films solar cells based on graphene oxide modified by Ni quantum dots

    12/01/2014
    SFRH/BPD/77704/2011

  • Strategic Project - LA 11 - 2011-2012

    12/31/2012
    PEst-C/CTM/LA0011/2011

  • Financial grant for participation to 9th European Conference on Application of Polar Dielectrics (ECAPD9)

    08/01/2008
    na

  • Structural analyses of doped SrTiO3 thin films

    2007
    COST-STSM-539-1258

  • STUDIES ON SRTIO3 BASED THIN FILMS PREPARED BY SOL-GEL FOR MICROELECTRONIC APPLICATIONS

    12/31/2008
    SFRH/BD/19861/2004

  • Structural properties of incipient ferroelectric films

    2005
    COST-STSM-525-00601

  • Preparation and characterization of thin films of incipient ferroelectrics

    2004
    POCTI/CTM/44732/2002

  • SGH - SMART GREEN HOMES

  • Development of tunable capacitors for applications at microwave frequencies

  • Thick composite films for piezoelectric devices

  • Development and characterization of composite electrodes based on porous graphene materials for energy storage devices

  • High performance composite electrodes for Na-ion capacitors

  • Controlling pseudo-dominant process for achieving both high-power and high-energy storage in electrochemical devices

  • Aerogel materials as sustainable electrodes for next generation supercapacitors

  • Sustainable functional materials for hybrid solid-state supercapacitors

  • COmposite electrodes For Flexible Electrochemical Energy STORagE devices

  • Flexible composite electrodes for high energy density hybrid devices

  • High performance pseudocapacitive electrodes for sodium-ion supercapacitors

  • Instituto de Materiais de Aveiro - CICECO UID/CTM/50011/2013

  • Centro de Tecnologia Mecânica e Automação

  • Centro de Tecnologia Mecânica e Automação

  • Centro de Tecnologia Mecânica e Automação

  • Multifunctional all-oxide nanostructures for electronic applications

  • PEERS Consortium - Erasmus+ Mobility Participants – Higher Education– Staff Mobility for Training

  • Sustainable Multiscale Engineering of high-Performance Oxide Composites for Energy Harvesting

  • Development and Investigation of Innovative Methods for Obtaining Functional Composite Materials of the Dielectric/Metal Type

  • Strontium titanate based films for tunable device applications

  • FAME - Functionalised advanced materials engineering of hybrids and ceramics

  • Funding of Strategic Projects with Public Interest promoted by Associated Laboratories and RD Units

  • Development of computational and physical tools to enhance the effectiveness of products and processes

Publications

  • On energy storage performance of K0.5Na0.5NbO3-based ceramics modified by Bi(Zn2/3(Nb0.85Ta0.15)1/3)O3

    Okhay, Olena; Tkach, Alexander
    Chemical Engineering Journal | 2026

    https://doi.org/10.1016/j.cej.2026.172818

  • PANI-coated Ni Nanotubes for Supercapacitors: Influence of Pore Size of the Applied Template and Fabrication Process Parameters

    O.Okhay
    The 6th International Electronic Conference on Applied Sciences (ASEC2025) | 2025

  • Insight into iodine-doped carbon xerogel electrodes on the capacitance and long-term stability of quasi-solid-state supercapacitors

    Arenillas, Ana; Brigandì, Antonino; Carbone, Alessandra; Chebil, Achref; Gatto, Irene; Lufrano, Francesco; Okhay, Olena; Squadrito, Gaetano
    Applied Surface Science | 2025

    https://doi.org/10.1016/j.apsusc.2025.164441

  • Towards Sustainability and Resilience of Modular Energy Islands

    Borg, Ruben Paul; et al; Fairbrother, Andrew; Finger, David Christian; Kádár, József; Okhay, Olena; Rajic, Milena; Tsami, Maria
    IOP Conference Series: Earth and Environmental Science | 2025

    https://doi.org/10.1088/1755-1315/1552/1/012040

  • Modular Floating Energy Islands with Green Hydrogen Integration: Design of a Small-Scale P2X Scheme

    Akpolat, Alper Nabi; Bakon, Tomasz; Cundeva, Snezana; et al; Finger, David C.; Okhay, Olena; Rexhepi, Vezir; Todorovic, Jovan
    IOP Conference Series: Earth and Environmental Science | 2025

    https://doi.org/10.1088/1755-1315/1552/1/012035

  • Effect of Anodic Aluminium Oxide Structure on the Electroless Ni-P Distribution into Nanopores

    Alexander Tkach; Boriana Tzaneva; João Ventura; Olena Okhay; Stela Atanasova-Vladimirova; Vesselina Milusheva
    Materials | 2025

    https://doi.org/10.3390/ma18163797

  • Comment on “Enhanced electromagnetic tunability of barium strontium titanate films via coating Pr modified yttrium iron garnet layer”

    Alexander Tkach; Olena Okhay
    Journal of Materials Science & Technology | 2025

    https://doi.org/10.1016/j.jmst.2024.10.048

  • Carbon and Related Composites for Sensors and Energy Storage: Synthesis, Properties, and Application

    Gil Gonçalves; Olena Okhay
    C | 2024

    https://doi.org/10.3390/c10040101

  • Comment on “Enhanced electromagnetic tunability of barium strontium titanate films via coating Pr modified yttrium iron garnet layer”

    A. Tkach; O.Okhay
    Journal of Materials Science and Technology | 2024

  • Initial Study of Reduced Graphene Oxide Foams Modified by Mn and Bi as Capacitive Electrode Materials

    Alexander Tkach; Olena Okhay; Tao Yang
    Nanoenergy Advances | 2024

    https://doi.org/10.3390/nanoenergyadv4040019

  • Energy geo-structures: A review of their integration with other sources and its limitations

    Elzbieta Halaj; et al; Francesco Cecinato; Lazaros Aresti; Maria Romana Alvi; Olena Okhay; Tao Fan; Zili Li
    Renewable Energy | 2024

    https://doi.org/10.1016/j.renene.2024.120835

  • A comprehensive review of the use of porous graphene frameworks for various types of rechargeable lithium batteries

    Okhay, Olena; Tkach, Alexander
    Journal of Energy Storage | 2024

    http://dx.doi.org/10.1016/j.est.2023.110336

  • Ceramics and Nanostructures for Energy Harvesting and Storage

    Alexander Tkach; Olena Okhay
    Nanomaterials | 2023

    https://doi.org/10.3390/nano13222912

  • Chemical Activation of Apricot Pit-Derived Carbon Sorbents for the Effective Removal of Dyes in Environmental Remediation

    Olena Okhay; Tetiana Boychuk; Vitalii Vashchynskyi
    C | 2023

    https://doi.org/10.3390/c9040093

  • Reduced graphene oxide for energy storage

    Alexander Tkach; O.Okhay; Otero-Irurueta, Gonzalo; Yang, Tao
    International Conference-Workshop on Functional Nanostructured Materials 4 (FuNaM-4), September 26th-29th, 2023, Krakow, Poland | 2023

  • Current Achievements in Flexible Piezoelectric Nanogenerators Based on Barium Titanate

    Alexander Tkach; Olena Okhay
    Nanomaterials | 2023

    https://doi.org/10.3390/nano13060988

  • Structure, Microstructure, and Dielectric Response of Polycrystalline Sr1-xZnxTiO3 Thin Films

    Alexander Tkach; Olena Okhay; Paula M. Vilarinho
    Coatings | 2023

    https://doi.org/10.3390/coatings13010165

  • Comment on “Enhancing the output performance of hybrid nanogenerators based on Al-doped BaTiO3 composite films: a self-powered utility system for portable electronics”, by B. Dudem, L. K. Bharat, H. Patnam, A. R. Mule and J. S. Yu, J. Mater. Chem. A, 2018, 6, 16101

    Okhay, Olena; Tkach, Alexander
    Journal of Materials Chemistry A | 2023

    http://dx.doi.org/10.1039/d3ta01041d

  • Metal Oxide Based Thermoelectric Materials

    Okhay, Olena; Tkach, Alexander
    Optical Properties of Metal Oxide Nanostructures | 2023

    http://dx.doi.org/10.1007/978-981-99-5640-1_13

  • Polyaniline—Graphene Electrodes Prepared by Electropolymerization for High-Performance Capacitive Electrodes: A Brief Review

    Alexander Tkach; Olena Okhay
    Batteries | 2022

    https://doi.org/10.3390/batteries8100191

  • Synergetic Effect of Polyaniline and Graphene in Their Composite Supercapacitor Electrodes: Impact of Components and Parameters of Chemical Oxidative Polymerization

    Alexander Tkach; Olena Okhay
    Nanomaterials | 2022

    https://doi.org/10.3390/nano12152531

  • Reduced Graphene Oxide—Polycarbonate Electrodes on Different Supports for Symmetric Supercapacitors

    Alexander Tkach; Alexandre Cunha Bastos; Kateryna Andreeva; Olena Okhay; Sampo Tuukkanen
    C | 2022

    https://doi.org/10.3390/c8010012

  • Low-Temperature Dielectric Response of Strontium Titanate Thin Films Manipulated by Zn Doping

    Alexander Tkach; Olena Okhay; Paula M. Vilarinho
    Materials | 2022

    https://doi.org/10.3390/ma15030859

  • Polar Phonon Behaviour in Polycrystalline Bi-Doped Strontium Titanate Thin Films

    Alexander Tkach; Dmitry Nuzhnyy; Jan Petzelt; Olena Okhay; Paula M. Vilarinho
    Materials | 2021

    https://www.mdpi.com/1996-1944/14/21/6414

  • Reduced graphene oxide based symmetric supercapacitors fabricated on copper and carbon tapes

    O.Okhay
    ANM 2021: 17th International conference on Advanced Nanomaterials, July 22-24, 2021, Aveiro, Portugal | 2021

  • Graphene/Reduced Graphene Oxide-Carbon Nanotubes Composite Electrodes: From Capacitive to Battery-Type Behaviour

    Alexander Tkach; Olena Okhay
    Nanomaterials | 2021

    https://www.mdpi.com/2079-4991/11/5/1240

  • Impact of Graphene or Reduced Graphene Oxide on Performance of Thermoelectric Composites

    Alexander Tkach; Olena Okhay
    C | 2021

    https://www.mdpi.com/2311-5629/7/2/37

  • Comment on “Hole-pinned defect-dipoles induced colossal permittivity in Bi doped SrTiO3 ceramics with Sr deficiency”

    Okhay, Olena; Tkach, Alexander
    Journal of Materials Science & Technology | 2021

    http://dx.doi.org/10.1016/j.jmst.2020.05.064

  • Comment on “Point defect structure of La-doped SrTiO3 ceramics with colossal permittivity”

    Okhay, Olena; Tkach, Alexander
    Scripta Materialia | 2021

    http://dx.doi.org/10.1016/j.scriptamat.2020.08.032

  • Energy storage of supercapacitor electrodes on carbon cloth enhanced by graphene oxide aerogel reducing conditions

    Gallo, Maria J. Hortiguela; Lufrano, Francesco; Mikhalev, Sergey; Okhay, Olena; Otero-Irurueta, Gonzalo; Staiti, Pietro; Tkach, Alexander
    Journal of Energy Storage | 2020

    http://dx.doi.org/10.1016/j.est.2020.101839

  • Long term durability of solid-state supercapacitor based on reduced graphene oxide aerogel and carbon nanotubes composite electrodes

    Lufrano, Francesco; Okhay, Olena; Staiti, Pietro; Tkach, Alexander
    Electrochimica Acta | 2020

    http://dx.doi.org/10.1016/j.electacta.2020.136540

  • Comment on “Giant dielectric response in (Nb + Zn) co-doped strontium titanate ceramics tailored by atmosphere”

    Okhay, Olena; Tkach, Alexander
    Scripta Materialia | 2020

    http://dx.doi.org/10.1016/j.scriptamat.2020.04.003

  • Effect of Solution Conditions on the Properties of Sol–Gel Derived Potassium Sodium Niobate Thin Films on Platinized Sapphire Substrates

    A.Santos; A.Tkach; I.Bdikin; M.E.Costa; O.Okhay; P.M.Vilarinho; R.Serrazina; S.Zlotnik
    Nanomaterials | 2019

    http://dx.doi.org/10.3390/nano9111600

  • Tuning electrical and thermoelectric properties of freestanding graphene oxide papers by carbon nanotubes and heat treatment

    A.Tkach; C.Dias; E.M.F.Vieira; G.Gonçalves; J.Ventura; L.M.V.Gonçalves; O.Okhay
    Journal of Alloys and Compounds | 2019

    http://dx.doi.org/10.1016/j.jallcom.2018.12.033

  • Thermoelectric performance of Nb-doped SrTiO3 enhanced by reduced graphene oxide and Sr deficiency cooperation

    A.J.S.Fernandes; et al; G.Otero-Irurueta; K.Orlinski; M.J.Hortiguela Gallo; O.Okhay; S.Zlotnik; W.Xie
    Carbon | 2019

    http://dx.doi.org/10.1016/j.carbon.2018.11.023

  • Structure, microstructure and electrical response of polycrystalline KNN thin films on platinized sapphire substrates

    O.Okhay et al.
    10th International Meeting `Electroceramics for End Users X - PIEZO 2019 | 2019

  • Stain Effect on the Properties of Polar Dielectric Thin Films

    A.Santos; A.Tkach; M.E.Costa; O.Okhay; P.M.Vilarinho; R.Serrazina; S.Zlotnik
    Advances in Thin Films, Nanostructured Materials, and Coatings | 2019

    http://dx.doi.org/10.1007/978-981-13-6133-3_32

  • Effect of bismuth doping on the properties of strontium titanate thin films

    A. Tkach; O.Okhay; P.M. Vilarinho
    Strontium Titanate: Synthesis, Properties and Uses | 2019

  • Strain-Mediated Substrate Effect on the Dielectric and Ferroelectric Response of Potassium Sodium Niobate Thin Films

    A.Santos; A.Tkach; I.Bdikin; M.E.Costa; O.Okhay; P.M.Vilarinho; R.Serrazina; S.Zlotnik
    Coatings | 2018

    http://dx.doi.org/10.3390/coatings8120449

  • Abnormal Grain Growth as a Method To Enhance the Thermoelectric Performance of Nb-Doped Strontium Titanate Ceramics

    A.Tkach; E.Guilmeau; J.Resende; K.V.Saravanan; M.E.Costa; O.Okhay; P.Diaz-Chao; P.M.Vilarinho
    ACS Sustainable Chemistry & Engineering | 2018

    http://dx.doi.org/10.1021/acssuschemeng.8b03875

  • Polar phonon behaviour in polycrystalline SrTiO3 thin films: the role of the substrate

    O.Okhay et al.
    6th International Conference "Nanotechnologies and Nanomaterials" NANO-2018 | 2018

  • Polar phonons in polycrystalline SrTiO3 thin films: The role of the substrate

    A.Tkach; D.Nuzhnyy; J. Petzelt; O. Okhay; P.M.Vilarinho
    Ferroelectrics | 2018

    http://dx.doi.org/10.1080/00150193.2018.1499407

  • Mechanical strain engineering of dielectric tunability in polycrystalline SrTiO3 thin films

    A.Tkach; I.M. Reaney; O.Okhay; P.M.Vilarinho
    Journal of Materials Chemistry C | 2018

    http://dx.doi.org/10.1039/c8tc00414e

  • Reduced Graphene Oxide -based Electrodes for the Energy Storage Devices

    O.Okhay et al.
    Advanced Nano Materials (ANM2017) | 2017

  • Giant dielectric permittivity and high tunability in Y-doped SrTiO3 ceramics tailored by sintering atmosphere

    A. Almeida; A.Tkach; O.Okhay; P.M.Vilarinho
    Acta Materialia | 2017

    http://dx.doi.org/10.1016/j.actamat.2017.03.051

  • Modification of thermoelectric properties of Nb doped SrTiO3 ceramics by reduced graphene oxide

    O.Okhay et al.
    Materiais 2017, XVIII Portuguese Materials Society Congress, VIII International Symposium on Materials | 2017

  • Manipulation of the power factor of reduced graphene oxide freestanding paper by temperature and addition of carbon nanotubes

    O.Okhay et al.
    Materiais 2017, XVIII Portuguese Materials Society Congress, VIII International Symposium on Materials | 2017

  • New Composite of Reduced Graphene Oxide with Potassium Chloride for Thermoelectric Applications

    O.Okhay et al.
    11th International Conference on Surfaces, Coatings and Nanostructured Materials (NANOSMAT 2016) | 2016

  • Thin film versus paper-like reduced graphene oxide: Comparative study of structural, electrical, and thermoelectrical properties

    A.Tkach; C.Dias; E.Titus; G.Gonçalves; J.Ventura; L.M.Valente Gonçalves; M.F.Ribeiro da Silva; O.Okhay
    Journal of Applied Physics | 2016

    http://dx.doi.org/10.1063/1.4958956

  • Manipulation of Electrical Conductivity of Graphene Oxide by Addition of Carbon Nanotubes and Heat Treatment

    O.Okhay et al.
    7th International conference on Advanced Nanomaterials, 2nd International conference on Graphene Technology, 1st International conference on Spintronics Materials (ANM2016) | 2016

  • Conductive Black-paper-like Reduced Graphene Oxide Obtained by Easy Way

    O.Okhay et al.
    6th International conference on Advanced nanomaterials (ANM2015) | 2015

  • Drastic modification of graphene oxide properties by incorporation of nickel: a simple inorganic chemistry approach

    A.Tkach; E.Titus; J.Gracio; J.Ventura; L.M.Guerra; M.Kläui; O.Okhay; R. Krishna
    Journal of Materials Science | 2015

    http://dx.doi.org/10.1007/s10853-015-8901-8

  • Photovoltage Study of Graphene Oxide with Ni Nanoparticles

    E.Titus; K.Andreeva; O.Okhay; O.Smirnov; R. Krishna; R.Savkina
    Materials Today: Proceedings | 2015

    http://dx.doi.org/10.1016/j.matpr.2015.04.051

  • Electrical and Magnetic Properties of Graphene Films with Ni Nanoparticles

    A.Tkach; E.Titus; J.Ventura; L.M.Guerra; M.Kläui; O.Okhay; R.Krishna
    Materials Today: Proceedings | 2015

    http://dx.doi.org/10.1016/j.matpr.2015.04.040

  • Influence of Oxidation and Deposition Process on Electrical Properties of Graphene Films

    E.Titus; J.Gracio; J.Ventura; LM. Guerra; O.Okhay; R. Krishna
    Journal of Materials Science and Engineering B | 2014

    http://dx.doi.org/10.17265/2161-6221/2014.10.007

  • Influence of oxidation and deposition process on electrical properties of graphene films

    O.Okhay et al.
    5th International conference on Advanced nanomaterials (ANM2014) | 2014

  • Synthesis and characterization of Spiky nickel nanoparticles-decorated reduced graphene oxide

    O.Okhay et al.; R.Krishna
    5th International conference on Advanced nanomaterials (ANM2014) | 2014

  • Enhanced resistive switching capability of RGO-MnO2 nanocomposite via incorporation of extra hydroxyl groups

    O.Okhay et al.
    5th International conference on Advanced nanomaterials (ANM2014) | 2014

  • A new hybrid material Ni/Ni(OH)2/rGO nanocomposite for memristor application

    O.Okhay et al.; R.Krishna
    5th International conference on Advanced nanomaterials (ANM2014) | 2014

  • Rapid Electrochemical Synthesis of Hydrogenated Graphene Oxide Using Ni Nanoparticles

    E.Titus; J.C.Gil; J.Ventura; O.Okhay; R. Krishna
    International Journal of Electrochemical Science | 2014

  • Manipulation of dielectric permittivity of sol–gel SrTiO3 films by deposition conditions

    A.Tkach; A.Wu; O.Okhay; P.M.Vilarinho
    Journal of Physics D: Applied Physics | 2013

    http://dx.doi.org/10.1088/0022-3727/46/50/505315

  • Electrical conductivity of LTA-zeolite in the presence of poly(vinyl alcohol) and poly(vinyl pyrrolidone) polymers

    E.Titus; et al; J.Gracio; J.Ventura; L.M.Guerra; M.Salimian; O.Okhay; R. Krishna
    Polymer International | 2013

    http://dx.doi.org/10.1002/pi.4542

  • Conductivity enhancement and resistance changes in polymer films filled with reduced graphene oxide

    E.Titus; J.Gracio; J.Ventura; L.M.Guerra; M.Salimian; O.Okhay; R. Krishna
    Journal of Applied Physics | 2013

    http://dx.doi.org/10.1063/1.4790608

  • Electrical properties of PVA (Polyvinyl alcohol)/Zeolite and PVP(PolyVinylPyrrolidone)/Zeolite composite

    M.Salimian; O.Okhay et al.
    International Conference on Polymer Behavior (ICPB5) | 2012

  • Magnetic Anomaly and Dielectric Tunability of (Sr,Mn)TiO3 Thin Films

    A.Tkach; A.Wu; O.Okhay; P.Borisov; P.M.Vilarinho; S.Bedanta; V.V. Shvartsman
    Ferroelectrics | 2012

    http://dx.doi.org/10.1080/00150193.2012.672038

  • Hydrogen Storage for Energy Application

    A.Rajkumar; E.Titus; et al; G.J.M.Sousa; M.Salimian; O.Okhay; R. Krishna; S.Rajendran
    Hydrogen Storage | 2012

    http://dx.doi.org/10.5772/51238

  • Dielectric relaxation of Sr1–1.5xBixTiO3 sol-gel thin films

    A.Tkach; A.Wu; O.Okhay; P.M.Vilarinho
    Journal of Applied Physics | 2011

    http://dx.doi.org/10.1063/1.3549612

  • Enhancement of tetragonality and role of strontium vacancies in heterovalent doped SrTiO3

    A. Almeida; A.Tkach; I. Gregora; J. Petzelt; J.A.Moreira; M.R.Chaves; O.Okhay; P.M.Vilarinho; T.M.Correia
    Applied Physics Letters | 2011

    http://dx.doi.org/10.1063/1.3549181

  • Role of trivalent Sr-substituents and Sr-vacancies in tetragonal and polar states of SrTiO3

    A. Almeida; A. Tkach; I. Gregora; J. Petzelt; J.A. Moreira; M.R. Chaves; O.Okhay; P.M. Vilarinho; T. M. Correia
    Acta Mater. | 2011

  • Dielectric response of polycrystalline Sr1-1.5xBixTiO3 thin films under direct current bias

    A.Tkach; A.Wu; O.Okhay; P.M.Vilarinho
    Applied Physics Letters | 2010

    http://dx.doi.org/10.1063/1.3463472

  • Low temperature dielectric characterization of Mg-doped SrTiO3 thin films prepared by sol-gel

    A.Tkach; A.Wu; O.Okhay; P.M.Vilarinho
    Applied Physics Letters | 2010

    http://dx.doi.org/10.1063/1.3360213

  • High dielectric constant and tunability of strontium titanate ceramics modified by chromium doping

    A.L. Kholkin; A.Tkach; O.Okhay; P.M.Vilarinho
    Journal of Physics: Condensed Matter | 2008

    http://dx.doi.org/10.1088/0953-8984/20/41/415224

  • Electric and Magnetic Properties of Incipient Ferroelectric Films Doped with Manganese

    O.Okhay et al.
    European Materials Research Society (E-MRS) Spring Meeting | 2008

  • Lattice dynamics studies of undoped and doped SrTiO3 films

    O.Okhay et al.
    DyProSo XXXI - 31st International Symposium on the Dynamic Properties of Solids | 2007

  • Microstructural studies and electrical properties of Mg-doped SrTiO3 thin films

    A.R.L. Ramos; A.Wu; E.Alves; I.M. Reaney; J. Petzelt; J.Pokorny; O.Okhay; P.M.Vilarinho
    Acta Materialia | 2007

    http://dx.doi.org/10.1016/j.actamat.2007.05.015

  • Dielectric permittivity and Cr3+ impurity ion probe luminescence in SrTiO3 sol–gel ceramics

    A.L. Kholkin; A.Tkach; I. Gregora; L. Jastrabik; M.E. Savinov; O.Okhay; P.M.Vilarinho; V.A. Trepakov
    Journal of the European Ceramic Society | 2007

    http://dx.doi.org/10.1016/j.jeurceramsoc.2007.02.022

  • Low-temperature dielectric properties of Zn-doped SrTiO3 thin films prepared by sol-gel

    O.Okhay et al.
    International Symposium on Integrated Ferroelectrics- ISIF 2007 | 2007

  • Low temperature dielectric relaxation of Sr1-1.5xBixTiO3 sol-gel thin films

    O.Okhay et al.
    10th International Conference and Exhibition of the European Ceramic Society - ECERS | 2007

  • Stress Influence on Dielectric Properties of Polycrystalline SrTiO3 Films

    O.Okhay et al.
    2007 MRS Fall Meeting | 2007

  • Surface and interface characteristics of polycrystalline SrTiO3 films on different substrates

    O.Okhay et al.
    INCOMAM´07 International Conference on Microscopy and Microanalysis XLII Congress of the Portuguese Microscopy Society | 2007

  • Stress effect on sol gel SrTiO3 films: structure, microstructure and electrical properties at room temperature

    O.Okhay et al.
    Electroceramics X | 2006

  • Polarization response and microscopic quantum paraelectricity in SrTiO3 sol-gel ceramic

    O.Okhay et al.; V.A. Trepakov
    Electroceramics X | 2006

  • Bi effect on the microstructure and dielectric properties of SrTiO3 thin films

    O.Okhay et al.
    Materiais 2005 - XII Portuguese Materials Society Meeting, III International Materials Symposium | 2005

  • SrTiO3 ceramics for tunable components: Sr-site substitution with Cr3+ and Mn2+

    A. Tkach; O.Okhay et al.
    EMSG 2005 | 2005

  • Stress-influence on the Properties of Mg doped SrTiO3 Thin Films

    O.Okhay et al.
    2005 MRS Fall Meeting | 2005

  • The Mg influence on the properties of SrTiO3 thin films

    A.Wu; O.Okhay; P.M.Vilarinho
    Journal of the European Ceramic Society | 2005

    http://dx.doi.org/10.1016/j.jeurceramsoc.2005.03.216

  • Preparation and Characterization of Zn doped SrTiO3 thin films

    O.Okhay et al.
    Junior Euromat 2004 | 2004

  • Microstructural studies of Mg doped SrTiO3 films

    O.Okhay et al.
    XXXIX Meeting of the Portuguese Society for Microscopy and Cell Biology | 2004

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