University of Groningen
Controlling spins in nanodevices via spin-orbit interaction, magnons and heat
Das, Kumar Sourav
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Publication date: 2019
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Das, K. S. (2019). Controlling spins in nanodevices via spin-orbit interaction, magnons and heat. University of Groningen.
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When I first arrived in the Netherlands after receiving a full scholarship to pursue the prestigious Topmaster Nanoscience course at the University of Groningen, little had I imagined about going on to do a PhD. It was during the second year of my masters that I realized my profound interest for doing experimental studies and research. With this realization, I took up the challenge of embarking on the PhD journey by dedicating four years of my life to experimental physics. As is common with almost all other PhD candidates, my journey hasn’t always been smooth either. At times when my boat hit the rough waters, there has always been some people who have stood by my side and motivated me to go on. I would like to take this opportunity to express my gratitude to everyone who has in some way or the other made this journey possible and memorable.
Firstly, I would like to thank my supervisors, Bart and Ivan, for giving me the op-portunity to work on an interesting and testing PhD project. Bart, it was an honour working in your research group, which is renowned in the spintronics community worldwide for non-local spin transport experiments in metals, two-dimensional ma-terials and magnetic insulators. You always took out time from your busy schedule to be available for discussing interesting results and giving fast and prompt feed-back (even when you were on holidays). I highly appreciate the trust you put in your PhD students, enabling them to design their own PhD projects and allowing them to work on different research ideas. This is clearly evidenced by the breadth of different research topics presented in this thesis.
Ivan, thank you for considering me as the right PhD candidate for your first EU FP7 research grant. Although you moved to Manchester almost immediately after I started with my PhD, you made sure to have regular contact with me and were
168 Acknowledgements always reachable. Thank you for the countless hours of Skype conversations which played a major role in all the chapters presented in this thesis. Your inquisitiveness and breadth of knowledge on various topics is truly inspirational and will continue to motivate me always.
I would like to thank Prof. Albert Fert, Prof. Tomas Jungwirth and Prof. Gerrit Bauer for being a part of my thesis assessment committee. Thank you all for your valuable time and very positive feedback. Gerrit, it has always been interesting to discuss my work with you. Thank you for sharing your ideas. I also fondly remem-ber the nice moments we shared in India during the ISIF conference.
I thank all my collaborators, who played an important role in the different work presented in this thesis. Carmine, Denys, Paola and Mario, it has been wonderful working with you all on the CNTQC project. Also, thanks for making all the CN-TQC project meetings and Top-Spin conferences exciting and enjoyable. Fasil, in the absence of Ivan in Groningen, during my starting months, you agreed to share your commendable nanofabrication skills with me. Thanks for sharing your knowledge and contributing with your numerical modelling skills in two publications, which we have co-authored. I highly appreciate your hard-working and kind nature. Wish you all the best in Loughborough. Jing, it was nice to collaborate with you on the out-of-plane spin injection project, which resulted in a good publication. Thank you for being a wonderful colleague, an office mate and also a flat mate. Good luck with finishing your thesis. I would also like to thank my two students, Wim and Martijn M., whom I supervised during my PhD. Thank you both for your dedication and contribution in two of the chapters in this thesis.
Anouk and Frank, a big thanks for agreeing to be my paranymphs and helping me out with the Dutch translation of my thesis summary. Anouk, you are an excel-lent researcher and have already managed to achieve several accolades. Keep it up! Frank, thanks for taking over my unfinished work. You are a fast learner and have solid presentation skills. Wish you the best with your PhD.
Tamalika di, thank you for being my mentor, not only during my masters, but also during my PhD. Whenever I was in a doubt, you were more than eager to listen to my problems and guide me. Thanks for all the short talks at your office, which inspired me and set me on the right track, whenever you sensed something is not going well. If you were a strict and inspiring mentor at work, you were no less than a caring elder sister away from the university. Cannot thank you enough for the delicious Bengali dishes with which you have treated many of us several times and made us feel at home. Thank you for everything.
I would like to extend my sincere gratitude to the technical and administrative support staff of our research group, without whom this work would have been im-possible. Thank you Johan, Martijn, Tom, Herman, Hans and Feitze for ensuring
that all the equipments and measurement setups are up and running. Johan, I en-joyed the small chats with you in the corridors. I admire the enthusiasm with which you do your work. Martijn, I cannot thank you enough for always helping me out with the wire-bonding of my complex device geometries. I trusted your expert pair of hands to do the magic every single time. Anna and Andrea, thank you for taking care of all the administrative issues. Also, thank you Anna for helping me and Ivan in the organization of the Top-Spin international workshop in Groningen.
My time in the Physics of Nanodevices research group wouldn’t have been so interesting and enjoyable without the group members. I would, therefore, like to thank all the past and present members of the FND group, with whom I have had the opportunity to work together: Caspar, Aisha, Alexey, Alok, Anouk, Arijit, Arjan, Carmem, Christian, Crystal, Danny, Eric, Frank, Gaurav, Geert, Gerjan, Jakko, Jan, Jasper, Jing, Jorge, Juan, Julian, Juliana, Lei, Ludo, Madhu, Magda, Mallik, Marcos, Nynke, Olger, Paul, Pep, Ping, Roald, Sander K., Sander O., Saurabh, Sid, Subir, Talieh, Tian, Timo, Tom, Xiangyang, Xu. Thank you all for the interesting discussions at work, during lunch, in the talks, and also for the fun-filled moments during our group outings, dinners and sport activities.
Apart from my research work, I have also been involved in several extra-curricular activities during my PhD, which have helped me unwind from my busy work sched-ules. I thoroughly enjoyed being the chairman of the 2016 PhD Day because of my wonderful team members. I would like to specially thank Musty, Aga, Isa, Alessio, Ionela, Monique, Estefania, Xu, Steven, Marleen and Yingqiu for the fun moments. I am also thankful to my friends from my Topmaster Nanoscience cohort: Musty, Sampson, Machteld, Alessio, Jamo and Nilesh for discussing our works during cof-fee breaks and keeping each other on track towards the completion of our PhD the-ses.
There are a few people whom I cannot thank enough for taking care of me when I had to be hospitalized during the first year of my PhD. Milon da, thank you for being by my side day and night, like my elder brother, during this difficult period. Akanksha, Arijit, Sid and Saurabh da, thank you too for all your support.
Living far away from your motherland and dealing with the challenging life of a PhD candidate can be stressful at times. I was lucky to be surrounded by people who made me feel at home during such situations. Subir da, Saurabh da, Milon da, Sid, Arijit, Akanksha, Dhwani, Soma, Harshad, Arunesh, Hemant, Ketan, Pulkesh, Shreya, Suresh, Sandeep, Mallik, Gurudas, Abhishek, Tarun, Ankur, RP, thanks for all the delicious meals which we used to cook together in the Yellow, Red and the Blue buildings. A Bengali is incomplete without Bengali food. I am most thankful to Soumen da, Soutri di, Asish da, Reema di, Pallab da, Rumki di, Jyotirmoy da,
170 Acknowledgements Parama di, Prabuddha da, Soma di, Swarnodeep da and Tanaya di for organizing the Bengali picnics at their places.
The last one and half year of my PhD has been quite special in my life. It is during this time, I met my wife, Mrinalini and her loving family. I am thankful to her and my in-laws (Ma, Baba, Samvedana, Siddhanth) for their continuous support during the final phase of my PhD. This is the period when I started to maintain a work/life balance and invest time in my spiritual development. This has helped me to manage my work efficiently and handle stress in a better way. Furthermore, I will always be grateful to all my family members back in India for their blessings and love.
Finally, I would like to express my unending gratitude towards the persons with-out whom I wouldn’t have been able to achieve any of these. I thank all my teachers, who have taught me things from as basic as the alphabets, to a subject as complex as nanoscience. Last but not the least, I thank and dedicate my work to my first teachers: my parents. Mum and Pappa, this is for you.
Kumar Sourav Das Waalre April 10, 2019
