|Visiting period:||15.01.2018 - 15.02.2018 (1 months)|
Institute Neél - CNRS
For my research stay I decided to visit the Institute Neél – CNRS, more specifically the group of Micro & Nano Magnetism (MNM) headed by Stefania Pizzini. With 450 employees, the institute Néel is one of the leading institutions for research in condensed matter physics. The institute also makes a high amount of contribution into magnetism and spintronics, which is also the main research topic of the MNM group.
Upon arrival, the group quickly integrated me into their working environment and helped me to understand, guide and teach their vastly researched topic, which is domain wall dynamics. During my stay, I learned about the dynamics of domain walls and domain wall motion manipulated by current pulses through spin transfer torque (STT). Additionally, I had the chance to collaborate with researchers from Spintec and gained much insight into spin related phenomena (many thanks to Laurent and Toshiki). The whole visit provided me with much needed knowledge and expertise that I will need for my PhD as for my future career path. The newly gained experience and insights will be a benefit for the future work within the project SFB 1261 in the analysis of domain wall behavior in the magnetostrictive layers of the sensors. Furthermore, with the work and obtained results during my stay in Grenoble a joint work publication is expected. With this, I would like to thank everyone that I had the pleasure meeting and working with, especially Jan and Stefania.
The city of Grenoble by itself is a really interesting place. Secluded between mountains and wrapped in the spirit of the Alps the city provides beautiful sceneries and various possibilities of activities in nature. The city by itself with its somewhat historical look gives the person living there a feeling of calmness, however during the day trams full of people running every some minutes shows the hustle and bustle of the dynamical life there. Grenoble is a relatively large city providing many versatile infrastructure as also multiple shopping possibilities around the city center as well as on the outskirts of it. People there are friendly and eager to help, if a visiting person looks like a lost tourist. The city has its fair share of international character however, I would recommend knowing at least some French words before visiting Grenoble.
In conclusion, the research stay was a success and provided a very positive outcome for me on a personal and professional level. For the other participants of the SFB 1261 I would definitely recommend Institute Neél and Grenoble as a wonderful possibility for an external research stay.
I gratefully thank the DFG as part of the CRC 1261 for giving me the opportunity through their funding to conduct this external research stay.
|Visiting period:||24.10.2017 – 18.12.2017 (2 months)|
|Visiting institution:||University of California, San Diego|
|Visiting scientists:||Prof. Oleg Shpyrko|
My stay abroad brought me to San Diego, right next to the Pacific Ocean and Mexico. My host was Prof. Oleg Shpyrko, he is a physicist and a leading scientist in coherent imaging techniques at synchrotron sources. He is a Professor and head of a group at the UCSD, University of California, San Diego.I arrived in San Diego on the 25th of October. It felt like the warmest day of the whole year for me and was, like all the other days in the next two months, sunny. The first people I got to know were my landlord and roommates. During my time in Pacific beach, one of many neighborhoods in San Diego, I got to know them quite well and we had a lot of fun and a great time. The first place I went was the beach. The beach was about 5 minutes away from the house and I took advantage of the proximity many times during my stay. The university was a 40 minutes bus ride away, along the scenic drive. As the name implies the way to the university has a beautiful view over the coastline of north San Diego. The campus of the UCSD is huge and you have many places to go and discover, for example the Geisel library known from the Inception movie. On the other hand, it feels local and small, and all the people are helpful and nice.
On my first day at the university, I had to do a lot of paper work and sign many documents. The American administrations love their paper work. After this first part, I got all my keys and cards and was a member/student of the UCSD. In the afternoon, I met my colleagues. They were from all over the world and we had a nice time together. I profited a lot from their knowledge about synchrotron sources, especially about coherent imaging techniques. Moreover, how to analyze and interpret the acquired measurements.
My everyday life at the university wasn’t that different from my well known work back in Kiel. We worked a huge part of the day at the computer and had from time to time a nice chat. On the other hand it differed. For example, the group has no laboratory of their own and I had to ask other scientist, to have a look at my sample and check them. And of cause, I had to learn about the new technique. I read and learn a lot, like in the beginning of the PhD phase.
An important part of my stay in the USA was a trip to the APS near Chicago. A third generation synchrotron, where we performed a coherent imaging experiment on samples related to the CRC 1261. Say what the samples were ZnO nanorods coated in gold with very special electrical and strain behaviour. This took place in cooperation with the Shpyrko group. DR. S. Hrkac accompanied me and guided me through the experiment and Ross harder the beamline scientist thought me how to use his instrument for my experiments as this was a new method for me. Thanks to their help, the experiment was a great success and we could visualize strain on nm length scales in the rods. The results are important for our SFB project A6 and most likely have a big influence on my own work. I am currently analyzing the data and aim to write a paper with the results this year.
In conclusion, I would encourage everybody to go to San Diego, enjoy this great city, the wonderful weather and this excellent university. I would like to thank the DFG for funding this research stay through CRC 1261.
|Visiting period:||29.9.2017 – 27.10.2017 (4 weeks)|
|Visiting institution:||University of Oregon, Eugene|
|Visiting scientists:||Prof. Dr. David C. Johnson|
Beginning of fall, I had the unique opportunity to visit Prof. Dave Johnson at the University of Oregon (UO) and the CAMCOR analytic laboratories for a research stay on behalf of project A6 within the CRC1261. The laboratories are equipped with two FEI dual-beam focused ion beam (FIB) scanning electron microscopes for performing advanced sample preparation necessary for a nano-structural analysis with the transmission electron microscope.
My personal aim of this research stay was to learn the FIB preparation method to do my own sample preparation and use the image corrected microscope for analysing magnetostrictive ultra-thin multilayer coatings of FeCo and TiN. These materials system is able to withstand higher temperatures up to 600°C and has a significant magnetostriction, which offers potential use as ferromagnetic layer for different sensor designs within the CRC.
Although my colleagues told me to be quite fast in learning the FIB technique, for me, all the drawbacks and failed preparation issues did darken my mood. Luckily, the sunny weather did all his best for me to resettle and the game and bingo nights with the colleagues to recover. In the end I did achieve all my aims to prepare and analyse a multilayer sample repaying for the days of struggle.
As part of the group of Dave and the CAMCOR facility I was lucky to get insight into various fields of research done at the UO and to re-establish ties in form of cooperation.
In conclusion, I really enjoyed my stay at the UO, the time at work in a multicultural and very friendly atmosphere and my time off enjoying the beautiful landscape of Oregon, the local football events and social evenings.
I am deeply grateful for this unique opportunity and experience in support by the IRTG program.
The funding for this research stay by the DFG is gratefully acknowledged within the CRC 1261.
|Visiting period:||07.09.2017 - 03.11.2017 (2 months)|
|Visiting institution:||Moscow Technological University (MIREA)|
|Visiting scientists:||Prof. Dr. Yuri Fetisov|
I visited the capital of the Russian federation for two months on behalf of project A7 within the CRC 1261. My host was Prof. Yuri Fetisov, who, with his group holds longstanding experience in the field of bulk magnetoelectric composites. Especially the converse ME effect was extensively studied and published.
The Moscow technological university, officially titled “Moscow Institute for Radio Engineering and Automation” (MIREA) is one out of over fifty institutions for higher education in the city. It has a capacity for just under 6000 students and it belongs to the smaller ones in the city of 12.4 million inhabitants. It is situated about 30 minutes by metro from the tourist center of the city, southwest of Moskva river.
The aim of the research stay was to gain experience with the well-established sensor characterisation method by means of a pickup coil. This method stems from the field of bulk magnetoelectrics, so its principal applicability to Kiel-made thin film composites had to be assured. In a second step the performance of the composites was evaluated and compared to the case for direct magnetoelectric interactions.
In the lab I got to know my PhD colleague, who is also the person in charge of the laboratory, his name is Fedor. He was very friendly and always helpful, especially in his role as mentor and interpreter in my handling of the perpetual language barrier. He kindly collected me at the station on the day of my arrival, welcoming me with two definite essentials in the city: A metrocard and a Russian SIM card, in order to receive the full benefit of two simply jaw dropping parts of Moscow`s infrastructure.
There’s no Moscow without metro. The rush hours can quite easily exceed two hours. The principal metro lines can’t be missed, running about every ninety seconds from five in the morning until one o’clock at night.
The puritanical and always affordable student house was just a short walk from MIREA. Concerning everyday life, the area had everything to offer, with three shopping malls and a few 24/7 supermarkets packed with interesting goods at prices comparable to home.
The time of my research stay gave me an impressive cross section of the temperature and weather dynamics of the country. Given the fact that the first ten days it was 25° and Mediterranean climate – life seemed nice and simple. Towards the end of my research stay I struggled with arbitrary weather conditions, including but not limited to, hail, snow, sleet showers and ice cold storms at temperatures of -5°.
Everyday life in Moscow as a German tourist is safe, even taking the last/first metro did not impair on my feeling of safety. Especially in the city center one encounters a high density of security personnel holding a surprisingly high level of privileges.
In conclusion the research stay was a successful and professionally seamless visit to the capital of the Russian federation. After two months the city and its people were still capable of supplying endless excitement, making time fly past. The knowledge and expertise, which I gained through my stay, is invaluable for the further pursuit of my PhD, some of the results obtained are planned to be published in a joint work.
Funding of this research stay by the DFG as part of the CRC 1261 is gratefully acknowledged.
|Visiting period:||30.01.2017 – 18.05.2017 (4 months)|
|Visiting institution:||Department of Chemical Engineering, Gleason Group
Massachusetts Institute of Technology (MIT)
Cambridge, MA, USA
|Visiting scientists:||Prof. Karen K. Gleason|
I spend my external research stay in the group of Prof. Gleason. The group belongs to the Department of Chemical Engineering at the MIT and has high expertise in chemical vapor Deposition (CVD) polymers.
My research was focused on low-k polymer dielectrics deposited by initiated chemical vapor deposition (iCVD). This is highly related to my work for the CRC 1261. The iCVD technique was used to deposit amorphous fluoropolymer thin films and organosilicon polymer-air composites on conductive substrates. The samples were characterized by impedance spectroscopy. The free volume of the polymer has a significant influence on the dielectric properties. Effective medium theory was used to evaluate the results.
|Visiting period:||31.08.2016 – 30.11.2016 (3 months)|
|Visiting institution:||Departamento De Sistemas Aeroespaciales, Transporte Aéreo y Aeropuertos
Univeridad Polytécnica de Madrid (UPM)
|Visiting scientists:||Prof. Dr. José Ignacio Izpura Torres
(Professor for Electronic Engineering)
My scientific work in Madrid treated the basic noise calculation of two port devices, the origin of the noise, and the underlying basic theory of the fluctuation-dissipation theorem. With the presently accepted theory, most noise calculations are valid and accurate for application, but leave room for interpretation. That is why Physicists like Callen and Welton in 1954 discussed on an extension to the theory made by Nyquist and Johnson in the 1930s, taking into account the fluctuation part. However, the lack of practical relevance led to a wide acceptance of considering only the dissipation part.
There are problems, where the noise calculation yields wrong solutions, especially when thermal equilibrium is not given. During my stay in Madrid I identified three such problems and discussed the approaches and their differences. As a proof, I checked the calculations with recent simulation tools to verify non-physical solutions.
Madrid is a city dazzling of different cultures, especially in the part where I lived, Lavapies. Especially in the less touristic regions and at work, English is not much spoken, so sharpen your Spanish.