University of Groningen
Novel phases in ferroelectric BaTiO3 thin films
Everhardt, Arnoud
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Everhardt, A. (2017). Novel phases in ferroelectric BaTiO3 thin films: Enhanced piezoelectricity and low
hysteresis [Groningen]: Rijksuniversiteit Groningen
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Download date: 18-06-2017
Acknowledgements
This piece of research, this thesis and all other developments would not have been possible
without the help of an extensive amount of people who all contributed in one way or another.
The first person I want to thank is Beatriz Noheda. As my promotor, supervisor and very kind
person you have first of all made it possible to do this PhD at this position. But there is much
more. You have not only helped guiding the research into the direction it has blossomed out to be,
but you are also a mentor on more than research alone. With different personalities and working
styles, you showed me another side of how things can be done, which has also enriched me as a
person – which is arguably even more difficult than the research itself. Your devotion to not only
science, but also to the people behind it, even when it does not necessarily benefit only your own
group, can be admired.
I also want to thank Thom Palstra. You might have left your own research now for the benefit of all
of science in this country, your view on research will never be forgotten. As my supervisor in both
my bachelor and master thesis, you have shown me that science is not to be taken lightly. It is an
important job to serve the world with the proper knowledge and you should always be extremely
critical and cautious of your interpretations, your results, even yourself. It is a lesson that will never
get lost. Also special thanks to Anne Arkenbout for showing me the first real steps into science
back in my bachelor with contagious enthusiasm.
While a research project usually starts quite lonely, with just you and your supervisor, we have
managed to bring the joy of this topic to more people outside of this little research group. The
longest collaboration has been with Sylvia Matzen. You started as a postdoc on many projects in
our group, so obviously you were also assigned to be ‘my’ postdoc. In a limited amount of time you
managed to get all the projects in the group to work together well with lasting impact even when
you moved to your beloved job in Paris. I can count myself lucky our collaboration did not end
there, and you continued to help our project with endless comments on what we had been seeing.
I would still have struggled now with small, tiny issues if it were not for you.
I have also had the pleasure to collaborate with Neus Domingo and Gustau Catalan in Barcelona,
who always welcomed me all those times I flew to you, ready to clog your PFM system day and
night. Always willing to help with whatever weird ideas I came up with, not only for measurements
on your system, but also conceptual ideas. Your devotion gave a real kick-start to all areas in my
research. Umesh, I had the pleasure of meeting you for one day in which you gave a real start for
the piezoelectric measurements, even though your measurements turned out not to be conclusive
enough to be used in the thesis.
Thibaud Denneulin, I am sad I have never met you in person, even though we have been in contact
for more than three years. You started early on helping us with our films, and as our combined
knowledge grew, you managed to get nice results, which turned out to be more amazing every
time we tried something new. I hope to meet you ‘in real life’ one day as you seem to be a very
nice person as well. Thanks to Etienne Snoeck, Martin Hÿtch and Cesar Magen for the additional
support on the TEM measurements. Yu-Tsun Shao and Jian-Min Zuo, your new TEM measurements
were so important that they have been added to the last chapter of this thesis at the last possible
moment, which increased its impact tremendously.
Anna Grünebohm, we first met in a conference just in the beginning of my last year, but we turned
it into an enormous discussion on the theory and experiments on these thin films. You are very
knowledgeable, patient and able to explain for the hundredth time what we had discussed the
week before. After my visit to you in Germany (as it is very close to home anyways) we thought we
had finally figured everything out – when everything changed again. I really enjoyed the endless
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discussions and I wonder if the last word will ever be said. I do know now whom to contact if I ever
need theory advice again.
There have been a couple of other contacts I am grateful for. Jirka Hlinka, you have been very
interested in our materials and were the first to contact me after my first oral presentation
abroad. Our collaboration is not yet finished and I am sure something will come out of it in the
future. Laurent Bellaiche, you have given us a good idea for a new direction of research which
unfortunately we have not carried out yet because of substrate delivery problems. Paul Muralt and
Robin Nigon, thank you for your advice on the measurement of piezoelectric materials. Dragan
Damjanovic, thank you for your suggestions on our written manuscript. I am also grateful to my
reading committee, Nava Setter, Guus Rijnders and Jeff de Hosson and I am honored that you have
been willing to read this extensive thesis.
Luckily not all contacts were from outside Groningen and also a lot of physical and mental help
was received within this lovely place. Jeroen Heuver, you are always interested in other people
and making sure that their research and equipment works, by working together for it. Saeedeh
Farokhipoor, you are knowledgeable and passionate about science and have the ability to ask
the right questions to get people thinking to the next level. Oleksiy Nesterov, we have worked
together on similar materials and you helped me in getting started in the beginning on this new
project for me. Justin Varghese, everyone always enjoyed your presence and I absolutely loved
being able to visit you in Kerala in India (still the most lovely piece of earth I have ever been).
Mart Salverda, I’m still amazed by how fast you went from learning everything to being the main
resource for people in the group for basically everything. You are too kind to everyone. Thank
you too for checking chapter 2 of this thesis. Mónica Acuautla Meneses, an engineer in a research
group doing fundamental science, what good can it bring? As it turns out, a lot of good things! It
brings a lot of new learning for everyone, and with your help the energy harvesting chapter of this
thesis has been improved a lot. Yingfen Wei, I have never seen someone failing with so much joy
as you do, which is a real superpower that can only be underestimated, as it brings you to new
heights that others cannot reach because they try to avoid failure. Jin Xu, only part-time group
member, but nobody could be accepted more than you.
I also want to thank all the other people I have interacted with in my time in this building. The
cleanroom help with mainly Johan, Martijn and Eric, and all the other people with Aisha, Guowei,
Anil, Laaya, Machteld, Geert, Liany, Graeme, Saurabh, Sander, Gaurav, Roald, Arijid, Paul, Alim,
Alex, Mai, Lei, Shiva, Syarif and Tomas.
Henriët van Mil-Boddeveld, you have helped me near the last phases of my PhD in ways I did not
expect I would need when I started. Henk Bonder, we all like you very much, not only are you
always ready to do what we ask within minutes, but you are also a very caring person for everyone.
I am sure you will keep doing better. Jacob Baas, it does not matter if it is a broken bike, a broken
soul or a broken theory or analysis, you will fix all those things for everyone. You are the social
anchor of the group and a one-in-a-kind in this group.
Jordi Antoja Lleonart and Silang Zhou, I was delighted to have you as my students. Not only did
I have to try my best to teach you something about your topic and the practice of doing science,
but also you have taught me something about teaching and about myself that I otherwise could
not have learned. Jordi, exceptionally organized, teaching me to be even more consistent, and you
have learned to get out of that box. Silang, you cannot be caught in a box, always trying out new
things, you taught me to prepare for anything. Please keep on surprising the people around you.
The group dynamics have been very interesting to be part of for those five full years (and up to
seven years ago including my bachelor). Everyone brought their own personal input in the group
process, and the group changed accordingly. Having lunch together, and important (unfortunately
less urgent) tea o’clock, or having food, drink and BBQ has been special all this time. I will miss all
this, but hope you continue having as much fun as when I was around.
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Acknowledgements
Normaal gesproken wordt de financiering van een project niet genoemd in de acknowledgements
van een these, maar in dit geval is het helemaal terecht om het wel te noemen omdat ik het
niet als financiering beschouw. De Aduarderkring, een groep alumni van deze universiteit heeft
besloten om mij te adopteren. Elk half jaar had ik het voorrecht om langs te mogen komen op de
bijeenkomst van deze geweldige groep mensen. Ze komen oorspronkelijk bij elkaar om de binding
met de universiteit weer iets op te zoeken, maar ze blijven bij elkaar omdat het zo’n mooie en
hechte groep is die in elkaar geïnteresseerd is. Ik voel me echt onderdeel van de familie en vind
het jammer dat ik ze nu moet verlaten. Ze waren niet alleen geïnteresseerd in de toepassingen van
mijn onderzoek (het onderzoek zelf is ook wel leuk, maar o zo lastig), maar ook in mij als persoon.
En een beter compliment dan ‘ik kom vooral voor jouw presentaties’ kan je niet krijgen. Ik moet
ook de uitstekende leiding vanuit het Ubbo Emmius Fonds, met Josca Westerhof als grootste
drijvende kracht achter dit project, bedanken, zonder wie dit allemaal nooit mogelijk was geweest.
Het is niet alleen maar studeren en werken in Groningen geweest in al die 9 jaar. Ik heb ook heel
veel plezier daarbuiten gehad met o.a. mijn duikclub Ad Fundum, het schaatsen bij Tjas, gewoon
met andere promovendi omgaan bij Gopher en improviseren bij onze improgroep. En gelukkig
heeft mijn familie ook geaccepteerd dat ik dit ben gaan doen, steun ondanks dat ze niets begrijpen
van wat ik nu eigenlijk doe. Als laatste, bedankt Jolanda Heijnen voor alles wat je gedaan hebt, en
alle vrijheid die je me gegeven hebt om al mijn rare plannen uit te voeren.
Arnoud Everhardt
La Paz, Bolivia (Februari 14, 2017)
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