On the 3rd, Aurèle Kamber started as Ph.D. student in the group. Aurèle received his Bachelor of Science and his Masters of Science both in Nanoscience from the University of Basel in 2019 and 2021, respectively. In September 2020, Aurèle completed joined our lab as a Masters student. After a short break, we are happy to announce that he now joins us for his Ph.D. Welcome back Aurèle!
On the evening of Friday the 3rd, the group go together along with some alumni for its annual end-of-the-year dinner. This year we celebrated with burgers and drinks at Valentino’s Place in Klein Basel. Thanks to all for a good time and to Dr. Boris Groß for suggesting the venue and organizing.
On the 3rd, Applied Physics Letters published our article entitled, Magnetic hysteresis of individual Janus particles with hemispherical exchange bias caps as a ‘Featured’ article. Janus particles are nano- or micron-sized particles with two sides, each having different physical or chemical properties. Magnetic Janus particles are a particularly interesting subset of these, because their translational and rotational motion can be controlled using externally applied magnetic fields. They can be used for applications ranging from acting as stirrers in lab-on-chip devices, transporters of biological cargo, or biosensors. Crucially, however, magnetic control depends on the particles being magnetized, i.e. they must have a remanent net magnetic moment. This is often not the case, especially in nano- or micron-sized objects.
In our work, we use torque magnetometry to measure the magnetic state of individual Janus particles. We find that although small ferromagnetic Janus particles have a vanishing remanent magnetic moment, we can engineer them to have a robust remanent moment by the addition of an additional antiferromagnetic layer. This promising result means that potentially useful nano- and micron-size magnetic Janus particles can indeed be mass produced.
The work represents a collaboration between our group and the group of Prof. Arno Ehresmann from the University of Kassel in Germany. Ph.D. student Simon Philipp and research scientist Dr. Boris Groß led the project and carried out the measurements and analysis. Mathias Claus, who is now a Ph.D. student in our group, and Marc Sulliger carried out initial measurements during their time as Masters students. Ph.D. students Meike Reginka and Maximillian Merkel from the Ehresmann group fabricated and characterized the samples.
On the afternoon of Thursday the 25th, the group took some time for leisure and fun. 16 of us piled into a van and 2 cars to go karting at the Sundgau karting track, just across the border in France. Despite the fog and chilly weather, everyone went out for 2 or 3 sessions of throwing the gas-powered karts around the track as fast as possible, including the occasional crash and even a track ban. Unfortunately, in our excitement, we managed to forget Mathias Claus at the Department! We’ll make it up to you Mathias. Thanks to all for a good time! Photos here.
On Tuesday the 23rd, Ph.D. student Thibaud Ruelle defended his thesis, entitled “Towards Hybrid Optomechanics in a Fiber-Based Fabry-Perot Cavity”, earning his doctorate in Physics summa cum laude. Richard Warburton chaired the exam with Prof. Poggio and Prof. Albert Schliesser (Copenhagen), who joined via teleconference, making up the committee.
Thibaud joined the lab as a Ph.D. student in January 2016 to work with Dr. Floris Braakman on his Ambizione research project on realizing an optomechancial tripartite system. In the meantime, he has built-up a state-of-the-art optomechanical setup and carried out first experiments on it. Congratulations to Dr. Ruelle!
From the 11th to the 12th, the Department hosted the first Site Visit of the NCCR SPIN. Experts from around the world listened to presentations and discussed posters with members of the consortium. On the 11th, Prof. Poggio gave a talk in the morning and Ph.D. student Luca Forrer presented a poster in the afternoon. The National Center of Competence in Research (NCCR) SPIN is based at the University of Basel with the objective of developing reliable, fast, compact, scalable spin qubits in silicon. Within the consortium, our group focuses on developing electron spin qubit devices.
From the Wednesday the 27th to Friday the 29th, a number of group members attended the “Computational materials discovery of unconventional magnets” workshop at EPFL in Lausanne, Switzerland. The workshop focused on unconventional magnetism and specifically on understanding, predicting, and realizing of quantum magnetic phases in real materials. Topics covered included quantum spin liquids, materials hosting skyrmion and non-colinear magnetic phases, and 2D magnets. Dr. Kousik Bagani, Dr. Estefani Marchiori, Dr. Floris Braakman, Hinrich Mattiat, Andriani Vervelaki, Daniel Jetter, and Matthias Claus attended from our group. Giulio Romagnoli also attended giving a contributed talk on the 29th entitled, “Real-space imaging of magnetic phases in Cu2OSeO3 crystal”. A program can be found here.
From the 4th to the 5th, our group hosted the first annual meeting of the FET-Open collaboration led by our group and entitled, “Focused Ion Beam fabrication of superconducting scanning Probes (FIBsuperProbes)“. This collaboration aims to enable a new era in scanning probe microscopy, in which nanometer-scale sensing devices – specifically superconducting devices – can be directly patterned on-tip and used to reveal new types of contrast. The principal investigators involved in the collaboration are Dr. Armin Knoll (IBM Zürich), Prof. José María De Teresa (Zaragoza), and Prof. Dieter Kölle (Tübingen). The meeting included a program of talks, a dinner, and plenty of time for discussion. Special thanks to Kousik Bagani and Claudia Wirth for helping with the organization. A full program can be found here.
On the 1st, Nature Reviews Physics published our paper entitled, Nanoscale magnetic field imaging for 2D materials. The article is a “Technical Review” covering sensitive magnetic scanning probe microscopies and their application to 2D materials. The review discusses how using these techniques to image the recently discovered correlated states hosted in 2D materials will provide crucial local information on quantum phases, including on the spatial variation of order parameters, the presence of domains, and the role of defects. It also addresses the importance of choosing the appropriate probe for the physical system under investigation: the different scaling of magnetization and current contrast with probe-sample spacing and the different physical quantities that are measured by each probe make certain techniques more amenable to certain systems. A link to a view-only PDF is here.
The paper was a collaboration between Prof. Poggio, post-doc Dr. Estefani Marchiori, former Ph.D. students and post-docs Dr. Lorenzo Ceccarelli and Dr. Nicola Rossi, and collaborators at ETH Zürich: Dr. Luca Lorenzelli and Prof. Christian Degen.
On the 1st, Liza Žaper started as Ph.D. student in the group. Liza completed her Bachelor of Science in 2014 at the University of Zagreb, Croatia and her Masters degree in 2017 at the Polytechnic University of Milan. Before joining our group she worked at the ETH in Zürich. Welcome Liza!