Dr. Lynette Keeney

Biography

Dr. Lynette Keeney is a Senior Researcher and Royal Society-Science Foundation Ireland University Research Fellow in Tyndall National Institute, University College Cork, focusing on the synthesis and understandings of room temperature multiferroic thin films. She is an inorganic chemistry graduate from National University of Ireland, Galway (PhD 2005), where she won five University awards. Before joining Tyndall in 2008, she worked as a Chemist in industry (Charles River Laboratories, Pre-clinical Services, Montreal Inc.). She continues to engage with industry on projects involving multiferroic materials development for data storage applications e.g. via a Science Foundation Ireland technology innovation award (2014) and through direct funding from Intel Corp. (2016). Dr. Keeney is a member of the International Advisory Board of ECAPD (European Conference on Applications of Polar Dielectrics), is Tyndall-UCC representative on the Microscopy Society of Ireland Council and is a panel reviewer for Royal Society proposal applications. She was an Irish representative for the COST (European Cooperation in Science and Technology) Action MP0904 (Single and multiphase ferroics and multiferroics with restricted geometries (SIMUFER)). Dr. Keeney is a member of the Royal Society of Chemistry (MRSC) and is member of the IEEE Ultrasonics, Ferroelectrics and Frequency Control Society. She was a session organiser and committee member for the IEEE Conference on Nanotechnology (Cork, 2018, approx. 400 delegates) and was local organising committee member for the International Symposium on Integrated Functionalities (Dublin, 2019). Dr. Keeney actively engages in public outreach activities e.g. school visits, work experience programmes, public events and has been invited to receptions (2016 and 2019) hosted by the President of Ireland, Michael D. Higgins and Mrs. Sabina Higgins, to mark International Women’s Day. In 2015 Dr. Keeney was awarded a prestigious Royal Society/Science Foundation Ireland University Research Fellowship for her research project: ‘Memories are made of this: Multiferroics Research for Future Generation Memories’ and she received the UCC Early Stage Researcher of the Year Award for 2015. Via her Royal Society Awards and her recently awarded SFI Frontiers for the Future Project (2020), Dr. Keeney is expanding her research team to explore how sub-unit cell characteristics influence multiferroic behaviour and if these fascinating multiferroic properties can persist close to unit-cell thicknesses.

Research Interests

My field of specialisation is in materials science, particularly in the synthesis, understandings and optimisation of room temperature ferroelectric and multiferroic thin films for beyond CMOS data storage applications.

The remarkable growth of the internet means that by 2025, the data created worldwide will be equal to a stack of DVDs that could reach the moon 23 times or circle Earth 222 times! Existing data storage solutions, based on either electric or magnetic information stored separately in single-bit devices, are already struggling to match the demand for data.

Considering this, it is now widely appreciated that technologies that can simultaneously combine electric and magnetic storage -so-called multiferroics- will permit up to an eight-times increase in the amount of information that can be stored. However currently, no such devices exist because the materials needed for this technology -multiferroics which work at room temperatures- are not only extremely rare but also remain to be proven to work at the dimensions required -typically around 10 nanometres- about 6000 times thinner than a human hair.

In 2013, I designed a material system (Aurivillius phase, Bi₆Ti_xFe_yMn_zO₁₈; B6TFMO) that exhibits unique multiferroic (ferroelectric and ferromagnetic) properties in a single homogeneous phase at ambient temperatures.Our initial reports have been breakthroughs in the field of multiferroics, as this is the only multiferroic demonstrating intrinsic ferroelectric/ferromagnetic properties to a defined confidence level (≥99.5%). Work supported by my Royal Society-Science Foundation Ireland University Research Fellowship has also demonstrated the reversible linear magnetoelectric switching necessary for practical magnetoelectric device applicationswhile significant advances have been made towards understanding the fundamental mechanisms governing ferromagnetism in this material.

While earlier work focused on non-epitaxial, 100 nm-thick B6TFMO films, a crucial requirement for materials targeted for miniaturised data storage applications is the enhancement of their functional properties at sub-10 nm dimensions. Although this is recognised within the multiferroics community as a challenging task, we have recently successfully synthesised sub-10 nm B6TFMO films by chemical vapour deposition processes. Ferroelectricity is confirmed in 5 nm (1 unit-cell thick) B6TFMO films, with tensile epitaxial strain enhancing the piezoresponse. In-plane ferroelectric switching is demonstrated at 1.5 (7 nm) unit-cell thickness. The persistence of stable ferroelectricity near unit-cell thickness in B6TFMO, both in-plane and out-of-plane, is significant and initiates possibilities for miniaturizing novel multiferroic-based devices.

Having already demonstrated ferroelectric switching in 5nm B6TFMO, the overarching aim of my current projects is therefore to demonstrate room temperature magnetoelectric multiferroic behaviour in multiferroic thin films at device-relevant thicknesses.

We are also exploring the influence that sub-unit cell defects have on promoting magnetic cation ordering, formation of charged domain walls and how they facilitate the formation of exotic polar vortexes, which are emerging research focuses in nano-electronics and domain wall devices.

Research Grants

Active Grants

• Project title: Making Memories: Ultra-thin Multiferroics for Disruptive Data Storage Technologies; Funding Body: Royal Society / Science Foundation Ireland University Research Fellowships Renewals 2020

Start Date: 21 June 2021; End Date: 20 June 2024; Award (Tyndall funding value): €414,437.75

• Project title: Optimisation of Single Phase Room Temperature Multiferroic Materials Enabling Next Generation Data Storage; Funding Body: Science Foundation Ireland Frontiers for the Future Project

Start Date: 1 Oct 2020; End Date: 31 Sept 2024; Award (Tyndall funding value): €431,184.87 (Direct funds)

• Project title: Linking the magneto-electric properties of novel multiferroic materials at the micro and nano- scale for beyond CMOS data storage technology; Funding Body: Royal Irish Academy-Royal Society International Exchanges 2019 Cost Share (Ireland)

Start Date: 1 Sept 2019; End Date: 31 August 2021; Award (Tyndall funding value): €14,785.00 (Direct funds)

• Project title: Correlation of magnetic and magnetoelectric properties with crystallite orientation and sub-unit cell characteristics in room temperature multiferroic materials; Funding Body: Royal Society / Science Foundation Ireland Research Fellows Enhancement Award

Start Date: 31 January 2018; End Date: 01 Feb 2022; Award (Tyndall funding value): €146,250.00

• Project title: Memories are made of this: Multiferroics Research for Future Generation Memories; Funding Body: Royal Society/Science Foundation Ireland University Research Fellowship

Start Date: 01 Oct 2015; End Date: 21 June 2021; Award (Tyndall funding value): €550,561.70

Publications

Refereed papers in primary journals

Kalani Moore, Eoghan N. O’Connell, Sinéad M. Griffin, Clive Downing, Louise Colfer, Michael Schmidt, Valeria Nicolosi, Ursel Bangert, Lynette Keeney* and Michele Conroy*, “Charged Domain Wall and Polar Vortex Topologies in a Room-Temperature Magnetoelectric Multiferroic Thin Film” ACS Applied Materials & Interfaces 2022 14 (4), 5525-5536 DOI: 10.1021/acsami.1c17383
Lynette Keeney, Louise Colfer, Michael Schmidt, “Probing Ferroelectric Behavior in Sub-10 nm Bismuth-Rich Aurivillius Films by Piezoresponse Force Microscopy”, Microscopy and Microanalysis, 1-11 (2021) doi:10.1017/S1431927621013726
Keeney, L., Saghi, Z., O’Sullivan, M., Alaria, J., Schmidt, M., Colfer, L., Persistence of ferroelectricity close to unit-cell thickness in structurally disordered Aurivillius phases, (2020) Chemistry of Materials. DOI: https://doi.org/10.1021/acs.chemmater.0c03454
Halpin, J. C., Schmidt, M., Maity, T., Pemble, M. E, Keeney, L., Compositional tuning of the Aurivillius phase material Bi5Ti3-2xFe1+xNbxO15 (0≤x≤0.4) grown by chemical solution deposition and its influence on the structural, magnetic and optical properties of the material, (2020) IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, DOI: 10.1109/TUFFC.2020.2997406
Keeney, L., Smith, R. J., Palizdar, M., Schmidt, M., Bell, A. J., Coleman, J. N., Whatmore, R. W., Ferroelectric Behavior in Exfoliated 2D Aurivillius Oxide Flakes of Sub-unit Cell Thickness, (2020) Advanced Electronic Materials, 6 (3), 1901264. Open access: https://cora.ucc.ie/handle/10468/9656.
Faraz, A., Ricote, J., Jimenez, R., Maity, T., Schmidt, M., Deepak, N., Roy, S., Pemble, M. E. and Keeney, L., Exploring ferroelectric and magnetic properties of Tb-substituted m = 5 layered Aurivillius phase thin films, (2018) Journal of Applied Physics, 123 (12), 124101. Open access: https://cora.ucc.ie/handle/10468/5723.
Keeney, L., Downing, C., Schmidt, M., Pemble, M. E., Nicolosi, V., Whatmore, R. W., Direct atomic scale determination of magnetic ion partition in a room temperature multiferroic material, (2017)Scientific Reports, 7 (1), 1737. Open access: https://www.nature.com/articles/s41598-017-01902-1.
Faraz, A., Maity, T., Schmidt, M., Deepak, N., Roy, S., Pemble, M. E., Whatmore, R. W., Keeney, L., Direct visualization of magnetic‐field‐induced magnetoelectric switching in multiferroic aurivillius phase thin films, (2017) Journal of the American Ceramic Society, 100, 3, pp. 975-987 (2017). Open access: https://cora.ucc.ie/handle/10468/3399.
Deepak, N., Carolan, P., Keeney, L., Zhang, P. F., Pemble, M. E., Whatmore, R. W., Bismuth Self-Limiting Growth of ultra-thin BiFeO₃ Films,(2015) Chemistry of Materials, 27 (19), pp. 6508-6515. Open access: https://cora.ucc.ie/handle/10468/7724.
Faraz, A., Deepak, N., Schmidt, M., Pemble, M. E. and Keeney, L., A Study of the Temperature Dependence of the Local Ferroelectric Properties of c-axis Oriented Bi₆Ti₃Fe₂O₁₈ Aurivillius Phase Thin Films: Illustrating the Potential of a Novel Lead-free Perovskite Material for High Density Memory Applications’, (2015) AIP Advances, 5, 087123 (2015). Open access: https://doi.org/10.1063/1.4928495.
Deepak, N., Carolan, P., Keeney, L., Pemble, M. E., WhatmoreR. W., Tunable nanoscale structural disorder in Aurivillius phase, n= 3 Bi₄Ti₃O₁₂ thin films and their role in the transformation to n= 4, Bi₅Ti₃FeO₁₅ phase, (2015) Journal of Materials Chemistry C, 3 (22), pp. 5727-5732. Open access: https://pubs.rsc.org/en/content/articlehtml/2015/tc/c5tc01064k.
Dey, G., Wrench, J. S., Hagen, D. J., Keeney, L., Elliott, S. D., Quantum chemical and solution phase evaluation of metallocenes as reducing agents for the prospective atomic layer deposition of copper, (2015) Dalton Transactions,44 (22), pp. 10188-10199. Open access: https://pubs.rsc.org/en/content/getauthorversionpdf/c5dt00922g.
Hagen, D. J., Povey, I. M., Rushworth, S. , Wrench, J. S., Keeney, L., Schmidt, M., Petkov, N., Barry, S. T., Coyle J. P., Pemble,M. E., Atomic layer deposition of Cu with a carbene-stabilized Cu (i) silylamide, (2014) Journal of Materials Chemistry C, 2 (43), pp. 9205-9214. Open access: https://pubs.rsc.org/en/content/getauthorversionpdf/c4tc01418a.
Goswami, S., Bhattacharya, D., Keeney, L., Maity, T., Kaushik, S. D., Siruguri, V., Das, G. C., Yang, H. Li, W., Gu, C-z., Pemble, M. E., Roy, S., Large magnetoelectric coupling in nanoscale BiFeO₃ from direct electrical measurements, (2014) Physical Review B,90, 104402. Open access: https://arxiv.org/pdf/1409.5859.pdf.
Schmidt, M., Amann, A., Keeney, L., Pemble, M. E., Holmes, J. D., Petkov, N., Whatmore, R. W., Absence of Evidence ≠ Evidence of Absence: Statistical Analysis of Inclusions in Multiferroic Thin Films, (2014) Scientific Reports, 4, 5712. Open access: https://www.nature.com/articles/srep05712.
Deepak, N., Caro, M. A., Keeney, L., Pemble, M. E., Whatmore, R. W., Interesting Evidence for Template-Induced Ferroelectric Behavior in Ultra-Thin Titanium Dioxide Films Grown on (110) Neodymium Gallium Oxide Substrates, (2014) Advanced Functional Materials, 24 (19), pp. 2844-2851. Open access: https://cora.ucc.ie/handle/10468/7725.
Jackson, N., Keeney, L., Mathewson A., Flexible-CMOS and biocompatible piezoelectric AlN material for MEMS applications, (2013) Smart Materials and Structures, 22 [11], 115033. Open access: https://www.academia.edu/5926616/.
Keeney, L., Maity, T., Schmidt, M., Amann, A., Deepak, N., Petkov, N., Roy, S., Pemble, M. E., Whatmore, R. W., Magnetic-Field-Induced Ferroelectric Switching in Multiferroic Aurivillius Phase Thin Films at Room Temperature, (2013) Journal of the American Ceramic Society,96 [8], 2339-2357. Open access: https://cora.ucc.ie/handle/10468/2928.
Deepak, N., Zhang, P., Keeney, L., Pemble, M. E., Whatmore, R. W., Atomic Vapour Deposition of Bismuth Titanate Thin Films, (2013) Journal of Applied Physics, 113, 187207. Open access: https://cora.ucc.ie/handle/10468/2931.
Palizdar, M., Comyn, T. P., Ward, M. B., Brown, A. P. , Harrington, J. P., Kulkarni, S., Keeney, L. , Roy, S., Pemble, M. E., Whatmore, R. W., Quinne, C., Kilcoyne, S. H., Bell, A. J., Crystallographic and Magnetic Identification of Secondary Phase in Oriented Bi₅Fe_0.5Co_0.5Ti₃O₁₅ Ceramics,(2012) Journal of Applied Physics, 112, 073919. Open access: https://cora.ucc.ie/handle/10468/2932.
Zhang, P. F., Deepak, N., Keeney, L., Pemble, M. E., Whatmore, R. W., The structural and piezoresponse properties of c-axis-oriented Aurivillius phase Bi₅Ti₃FeO₁₅ thin films deposited by Atomic Vapor Deposition, (2012) Appl. Phys. Lett. 101, 112903. Open access: https://cora.ucc.ie/handle/10468/2933.
Keeney, L., Kulkarni, S., Deepak, N., Schmidt, M., Petkov, N., Zhang, P. F., Cavill, S., Roy, S., Pemble, M. E., Whatmore, R. W., Room Temperature Ferroelectric and Magnetic Investigations and Detailed Phase Analysis of Aurivillius Phase Bi₅Ti₃Fe_0.7Co_0.3O₁₅Thin Films, (2012) Journal of Applied Physics, 112 (5), 052010. Open access: https://cora.ucc.ie/handle/10468/2989.
T. Maity, S. Li, L. Keeney, S. Roy, ‘Ordered magnetic dipoles: controlling anisotropy in nanomodulated continuous ferromagnetic film’, (2012) Physical Review B, 86, 024438. Open access: https://cora.ucc.ie/handle/10468/2930.
Keeney, L., Groh, C., Kulkarni, S., Roy, S., Pemble M. E., Whatmore,R. W., Room Temperature Electromechanical and Magnetic Investigations of Ferroelectric Aurivillius Phase Bi₅Ti₃(Fe_xMn_1-x)O₁₅ (x = 1 and 0.7) Chemical Solution Deposited Thin Films, (2012) Journal of Applied Physics, 112 (2), 024101. Open access: https://cora.ucc.ie/handle/10468/2990.
Varghese, J., Barth, S., Keeney, L., Whatmore, R. W., Holmes J. D., Nanoscale Ferroelectric and piezoelectric properties of Sb₂S₃ Nanowire Arrays, (2012) Nano Letters, 12, pp. 868-872. Open access: https://cora.ucc.ie/handle/10468/6762.
Salaün, A., Newcomb, S. B., Povey, I. M., Salaün, M., Keeney, L., O’Mahony, A. Pemble, M. E., Nucleation and Chemical Transformation of RuO₂ Films Grown on (100) Si Substrates by Atomic Layer Deposition, (2011) Chemical Vapor Deposition, 17 (4-6), pp. 114-122. DOI: https://doi.org/10.1002/cvde.201006882.
Keeney, L., Zhang, P. F., Groh, C., Pemble, M. E., Whatmore, R. W., Piezoresponse force microscopy investigations of Aurivillius phase thin films, (2010) Journal of Applied Physics, 108 (4), 042004; Open access: https://cora.ucc.ie/handle/10468/2991.
Rao, J., Keeney, L., Winfield, R., Moth-eye-structured light-emitting diodes’, (2010) Optics Communications, 283, 2446. DOI: https://doi.org/10.1016/j.optcom.2010.01.056.
Conway, S., Keeney, L., Hynes, M.J., Anomalously slow rates of reduction of iron(III) polypyridine complexes by triphenyl verdazyl radicals in acetonitrile, (2009) Dalton Transactions, 15, 2878. DOI: 10.1039/B818766E.
Keeney, L.,Hynes, M. J., Kinetics and mechanisms of the electron transfer reactions of oxo-centred carboxylate bridged complexes, [Fe₃(µ₃-O)(O₂CR)₆L₃]ClO₄, with verdazyl radicals in acetonitrile solution, (2005) Dalton Transactions, 8, 1524. DOI: 10.1039/B418809H.
Keeney, L.,Hynes, M. J., Electron transfer reactions of tris(polypyridine)cobalt(III) complexes, [Co(N-N)₃]³⁺, with verdazyl radicals in acetonitrile solution, Dalton Transactions, 1, 133 (2005). DOI: 10.1039/B412569J.

Book Chapters

Lynette Keeney, Ian Povey: In book ‘Tailored Functional Oxide Nanomaterials’, “Vapor Phase Growth of Metal‐Oxide Thin Films and Nanostructures”, DOI:10.1002/9783527826940.ch1Keeney, L., Schmidt, M., Amann, A., Maity, T., Deepak, N., Ahmad, F., Petkov, N., Roy, S., Pemble, M. E., Whatmore, R. W., Novel approaches for genuine single phase room temperature magnetoelectric multiferroics, (2016) in ‘Nanoscale Ferroelectrics and Multiferroics’, WILEY, Chapter 25, 789-829; Open access: https://cora.ucc.ie/handle/10468/7729.

Contributions to symposia and compiled volumes

Lynette Keeney invited presentation titled “Discoveries of “Hidden” Topologies Occurring Intrinsically Within a Multiferroic Matrix” at the MRS Fall Meeting and Exhibit 2022 at the Symposium Session “EQ08: Higher-Order Topological Structures in Real Space: From Charge to Spin”, November 29^th 2022.
Lynette Keeney, “Scanning Probe Microscopy Investigations of Ultra-thin Aurivillius Phase Ferroelectrics“ at 2nd Joint Symposium of the Microscopy Society of Ireland and the Scottish Microscopy Society, Galway April 6th-8th 2022.
Louise Colfer (PhD supervised by Lynette Keeney), “Influence of Vicinal Surfaces on the Properties of Multiferroic Aurivillius Phase Thin Films“ at 2nd Joint Symposium of the Microscopy Society of Ireland and the Scottish Microscopy Society, Galway April 6th-8th 2022.
Louise Colfer, “Influence of Vicinal Surfaces on the Properties of Multiferroic Aurivillius Phase Thin Films“ at 2nd Joint Symposium of the Microscopy Society of Ireland and the Scottish Microscopy Society, Galway April 6th-8th 2022. •
Louise Colfer won the Thermo Fisher Scientific Best Poster Prize at the 2nd Joint Symposium of the Microscopy Society of Ireland and the Scottish Microscopy Society, Galway April 6th-8th 2022.

Lynette Keeney: “Probing the influence of defects and interfaces on the multiferroic behavior of layered Aurivillius phase thin films”, Electronic Materials and Applications 2022, American Ceramic Society conference (due to be in Orlando, Florida but took place on-line 19-21 Jan 2022).
Lynette Keeney: “Memories are made of this: My journey into the development of new multiferroic materials”, Invited virtual presentation 28 March 2022 for the Kerala State Higher Education Council Government of Kerala Sponsored ERUDITE – SCHOLAR IN RESIDENCE PROGRAMME. Bishop Moore College, Department of Chemistry, Mavelikara, India.Jackson, N., Olszewski, O. Z., Keeney, L.,Blake, A., Mathewson, A., A Capacitive Based Piezoelectric AlN Film Quality Test Structure, (2015) Proceedings of the 2015 International Conference on Microelectronic Test Structures, pp. 193-197. Open access: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7106139; DOI: 10.1109/ICMTS.2015.7106139
Dey, G., Elliott, S. D., Wrench, J., Keeney, L., Pemble, M. E., Organometallic reagents ZnEt2 and metallocene to be used for the reduction of copper for its atomic layer deposition: A study through DFT, (2014) Abstracts of Papers of the American Chemical Society, 10-August-2014.
Deepak, N., Zhang, P., Keeney, L., Pemble, M. E., Whatmore, R. W., Atomic Vapour Deposition of Bismuth Titanate Thin Films, (2012) ISAF/ECAPD/PFM, 2012 Intl. Symp., 9 – 13 July, 2012. Open access: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6297829
Palizdar, M.,Comyn, T. P., Ward, M. B., Brown, A. P., Harington, J., Kulkarni, S., Keeney, L., Roy, S., Pemble, M. E., Whatmore, R.W. , Quinne, C., Kilcoyne, S. H., Bell, A. J., Crystallographic and magnetic identification of secondary phase in orientated Bi₅Fe_0.5Co_0.5Ti₃O₁₅ ceramics, (2011) ISAF/PFM Intl. Symp., 24-27 July 2011, Vancouver, BC., 1-4. Open access: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6013995
Palizdar, M., Comyn, T., Kulkarni, S., Keeney, L.,Roy, S., Pemble, M.E., Whatmore, R.W., Bell, A. J., Synthesis of Platelets Bi₅Ti₃Fe_0.5Co_0.5O₁₅ via the Molten Salt Method, (2010) IEEE ISAF Int. Symp. 1-4. DOI: 10.1109/ISAF.2010.5712254.

Professional Activities

Member of the Royal Society of Chemistry, Microscopy Society of Ireland, European Microscopy Society, IEEE Ultrasonics, Ferroelectrics and Frequency Control Society.

Public Engagement

My team and I perform a range of outreach activity engagements such as the HighTechElec Transition Year Work Experience Programme, the “Teen Turn” programme, the BT Young Scientist and Technology Exhibition, the Blackrock Castle Observatory Science Café, the Royal Society of Chemistry Careers in Chemistry, the Cork City Council/SFI Carnival of Science, Discovery Exhibition, SFI Science Week Ireland, Nano Week, and the Cork Science Festival, Celebrate Open Science as well as in-person and virtual primary school visits.

Media publications/interviews:

Irish Times National newspaper (25 July 2019): https://www.irishtimes.com/business/innovation/better-data-storage-through-chemistry-1.3959109

The Royal Irish Academy (08 August 2019): https://www.ria.ie/news/grants-and-awards-royal-irish-academy-royal-society-international-exchange-cost-share-0

The Royal Society (June 2018): https://royalsociety.org/grants-schemes-awards/grants/university-research/lynette-keeney/

Silicon Republic (15 June 2016): https://www.siliconrepublic.com/people/research-researcher-tyndall-ucc-cork

Science Spin (Issue 50, Page 21, 2012): https://issuu.com/spin35/docs/s50_public_all