Loris starts as Ph.D.

On the 6th, Loris Durante started work as a Ph.D. student in the group. Loris received his Bachelor of Science in 2022 and his Master of Science in 2024 both in Physics from the University of Basel. He carried out both his Master project and thesis in our group on the fabrication, characterization, and optimization of SQUID-on-tip sensors for operation below 1 K. After successfully defending his work, he decided to join the group as a Ph.D. student. Welcome!

Prof. Poggio at IIT

On the evening of the 13th, Prof. Poggio visited the Istituto Italiano di Tecnologia (IIT) outside of Genova, Italy. On the invitation of the director, Dr. Giorgio Meta, Prof. Poggio visited the labs and discussed potential collaborations between the IIT and the Swiss Nanoscience Institute (SNI). In the late morning, he gave a talk entitled, “Magnetic imaging on the nanometer scale”. 

End-of-year Group Dinner

On the evening of the 4th, the group held its annual year-end dinner, this time at Pizzeria Dio Mio in downtown Basel. 37 people showed up between group members, alumni, and friends and enjoyed a lively evening of food, drink, and conversation. See you next year!

PRL Publishes Paper on Coupling Ions to a Nanowire

On Monday the 25th, Physical Review Letters published a paper entitled, Coupling trapped ions to a nanomechanical oscillator, on our implementation of a hybrid system combining a metallic nanowire with laser-cooled ions in a miniaturized ion trap. Operating the experiment in the classical regime, we demonstrate resonant and off-resonant coupling of the two systems and the coherent motional excitation of the ion by the mechanical drive of the nanowire. The results prove the feasibility of mechanically coupling ions to nanooscillators and open up avenues for mechanically manipulating the motion of trapped ions as well as for the development of ion-mechanical hybrid quantum systems.

The work was carried out by Ph.D. student Moritz Weegen and pursued in the research group of Prof. Stefan Willitsch in the Department of Chemistry of the University of Basel. Prof. Poggio served as Moritz’s co-advisor on the project and advised the team as an expert in nanowire mechanics.

Liza Earns Ph.D. and Claire Donnelly Visits

On Thursday the 21st, Ph.D. student Liza Žaper defended her thesis, entitled, “Exploring nanomagnets for quantum devices with NV magnetometry”, earning her doctorate in physics cum laude. The defense was chaired by Prof. Andrea Hofmann with Dr. Claire Donnelly (MPI CPfS), Prof. Poggio, Prof. Patrick Maletinsky, and Dr. Floris Braakman making up the committee.

After obtaining her Masters degree from the Polytechnic University of Milan in Electronics Engineering and working at the ETH in Zürich, Liza joined our lab in September 2021. Finishing her doctorate in just over 3 years, Liza has managed to do so faster than any previous student in the lab. Congratulations to Dr. Žaper!

On the same day, our external expert, Dr. Claire Donnelly, visited the lab and the department. In the afternoon, she gave a special seminar entitled, “Exploring three dimensional spin systems – and beyond“.

Prof. Poggio in Dresden

On the 14th to the 15th, Prof. Poggio visited colleages in Dresden, Germany on the invitation of Dr. Denys Makarov of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), just outside of Dresden. On Thursday the 14th, Prof. Poggio visited HZDR and gave a seminar entitled, “Magnetic microscopy of 2D and chiral magnetism”. The following day, Prof. Poggio visited colleagues including Dr. Thomas Mühl and Dr. Claire Donnelly at the Leibniz Institute for Solid-state and Materials Research (IFW) and the Max Planck Institute for Chemical Physics of Solids (MPI CPFS), respectively. He gave a seminar with the same title at MPI on the afternoon of Friday the 15th.

Estefani Speaks at Skymag 2024

From the 28th to the 30th, post-doctoral researcher Dr. Estefani Marchiori attended Skymag 2024 in Paris, France. The workshop concentrated on recent advances in the field of topological magnetic textures: in particular, the static and dynamic properties of skyrmions and antiskyrmions in ferromagnets and antiferromagnets,  the emergence of new skyrmionics materials, novel 2D and 3D topological structures as well as the applications of these magnetic textures. On the morning of the 28th, Estefani gave a talk entitled, “Imaging magnetic spiral phases, skyrmion clusters, and skyrmion displacements at the surface of bulk Cu₂OSeO₃“.

FIBsuperProbes Annual Meeting

On the afternoon of the 24th, our FET Open collaboration, ‘FIBsuperProbes‘ held its 4th and final annual meeting. The meeting was conducted online and included talks from members of each of the nodes: CSIC in Zaragoza, Spain; IBM Research in Zürich, Switzerland; University of Tübingen, Germany; and the coordinating node here at the University of Basel. The project is in its final year and will conclude in March 2025 with a final in-person meeting in Brussels, Belgium.

The project has produced remarkable results, especially in develping the SQUID-on-lever sensor technology that our group now employs for some magnetic imaging tasks. The original vision of the project was to enable a new era in scanning probe microscopy (SPM), in which nanometer-scale sensing devices – specifically superconducting devices – could be directly patterned on-tip and used to reveal new types of contrast. To realize this vision, we relied on focused ion beam (FIB) techniques to produce sensors with unprecedented size, functionality, and sensitivity directly on the tips of custom-designed cantilevers. The key to this undertaking has been the unique capability of FIB to mill, grow, or structurally modify materials – especially superconductors – at the nanometer-scale and on non-planar surfaces. The imaging techniques that resulted have significantly surpassed state-of-the-art SPM and are now helping us to unravel poorly understood phenomena in physics, chemistry, and material science.

Colloquium in Budapest

On the 22nd, Prof. Poggio gave the Leó Szilárd Colloquium at the Institute of Physics of the Budapest University of Technology and Economics with a talk entitled, “Magnetic microscopy of 2D and chiral magnetism”. Prof. Poggio also visited various researchers at the institute on the 21st and the 22nd, including collaborators Prof. Péter Makk and Prof. Sándor Bordács.

New shared Ph.D. starts

On the 7th, Patrick Raif started as an SNI Ph.D. student in both our group and the group of Prof. Andrea Hofmann in October 2024. Patrick received both his Bachelor of Science and Master of Science in Physics from the University of Konstanz in 2021 and 2024, respectively. For his Bachelor thesis, he spent 5 months working at the Institut Néel in Grenoble, France.

Nano Letters Publishes Paper on Strain in 2D Magnet CrSBr

On the 4th, Nano Letters published our article entitled, Imaging Strain-Controlled Magnetic Reversal in Thin CrSBr, on the role of inhomogeneous strain in the two-dimensional (2D) magnet CrSBr. 2D materials are extraordinarily sensitive to external stimuli, making them ideal for studying fundamental properties and for engineering devices with new functionalities. One such stimulus, strain, affects the magnetic properties of the layered magnetic semiconductor CrSBr to such a degree that it can induce a reversible antiferromagnetic-to-ferromagnetic phase transition. In this work, using scanning SQUID-on-lever microscopy, we directly image the effects of spatially inhomogeneous strain on the magnetization of layered CrSBr, as it is polarized by a field applied along its easy axis. The evolution of this magnetization and the formation of domains is reproduced by a micromagnetic model, which incorporates the spatially varying strain and the corresponding changes in the local interlayer exchange stiffness. The observed sensitivity to small strain gradients along with similar images of a nominally unstrained CrSBr sample suggest that unintentional strain inhomogeneity influences the magnetic behavior of exfoliated samples.

The study was led by Ph.D. student Andriani Vervelaki and former post-doctoral researcher Dr. Kousik Bagani. The latter two carried out the imaging experiments with support from Ph.D. student Daniel Jetter, who produced the SQUID-on-lever sensors. Research scientist Dr. Boris Groß provided input on the micromagnetic simulations. Collaborators from Columbia University in the groups of Profs. Xavier Roy and Cory Dean provided the 2D magnet samples. Former Ph.D. student and current post-doctoral researcher Märta Tschudin from Prof. Patrick Maletinksy’s group here in Basel helped conceive the collaborative project, after measurements on similar samples were carried out in the Maletinsky group.

Francesco and Aris at Workshop in Grenoble

From September 30th to October 1st, post-doctoral researcher Dr. Francesco Fogliano and Ph.D. student Aris Lafranca attended the 9th annual GDR MecaQ & Nanomeca Meeting in Grenoble, France. This meeting gathers the community of scientists — in France and nearby countries — sharing an interest for quantum optomechanics, nanomechanics, and associated phenomena and applications. Francesco gave a talk on the 1st entitled, “hBN optomechanical induced transparency and gain”, while Aris presented a poster, for which he won the best poster prize. Congratulations!

Mirco at Summer School in Trieste

From September 23rd to October 4th, Masters student Mirco Schwarz atteded the School and Workshop on Frontiers of Nanomechanics at the International Cetre for Theoretical Physics (ICTP) in Trieste, Italy. The school covered fundamental concepts of nano- and optomechanical systems and introduced the key concepts behind future nano- and optomechanical technologies. It included lectures on coupling nanomechanics to spins, nonlinear dynamics, topological systems, cavity optomechanics, foundations, coupling to qubits, and non-Hermitean physics. The lectures reflected the fields, which currently attract the highest scientific interest and/or application potential. The students also worked on mini-projects and had the chance to present their work in a poster session.

Paper Published on Imaging Magnetic Phases in Cu₂OSeO₃

On the 28th, Communications Materials published our article entitled, Imaging magnetic spiral phases, skyrmion clusters, and skyrmion displacements at the surface of bulk Cu₂OSeO₃, in which we use scanning SQUID microscopy to image the surface of bulk Cu₂OSeO₃ at low temperature. Real-space maps measured as a function of applied field reveal the microscopic structure of the magnetic phases and their transitions. In low applied field, we observe a magnetic texture consistent with an in-plane stripe phase, pointing to the existence of a distinct surface state. In the low-temperature skyrmion phase, the surface is populated by clusters of disordered skyrmions, which emerge from rupturing domains of the tilted spiral phase. Furthermore, we displace individual skyrmions from their pinning sites by applying an electric potential to the scanning probe, thereby demonstrating local skyrmion control at the surface of a magnetoelectric insulator.

The work was led by post-doctoral researcher Dr. Estefani Marchiori, who along with former Ph.D. student Dr. Giulio Romagnoli carried out the experiments and analyzed the data. Ph.D. student Lukas Schneider did the magnetic force microscopy (MFM) measurements using ultrasensitive magnet-tipped nanowires (NWs) and research scientist Dr. Boris Groß carried out micromagnetic simulations. The Cu₂OSeO₃ crystals were grown by Dr. Priya Baral and Dr. Arnaud Magrez from EPFL, while the NWs for MFM were grown by collaborators in the Budakian group at the University of Waterloo, Canada. Together with Estefani, Dr. Jonathan White from the PSI carried out small angle neutron scattering measurements on the sample. The project was the result of collaborations started during the ‘Nanoskyrmionics’ Sinergia Project led by Prof. Dirk Grundler from EPFL.

Group trip to Crete

From the 19th to the 22nd, a subset of the group and friends traveled to the island of Crete, Greece for a weekend of sun, food, and outdoor activities. Special thanks to Ph.D. student Andriani Vervelaki for organizing and serving as our local guide to her beautiful island.

Swiss Physical Society Meeting

From the 9th to the 13th, the Swiss Physical Society (SPS) Annual Meeting was held at the ETH Zürich. Prof. Poggio attended a session on “Spintronics and magnetism at the nanoscale” on Tuesday the 10th and Thursday the 12th. He gave a talk in this session on the 10th entitled, “Scanning SQUID-on-tip microscopy of 2D and chiral magnetism”.

2024 SNI Annual Meeting

From the 4th to the 6th, students Lukas Schneider, Luca Forrer, and Prof. Poggio were in Meisterschwanden, Switzerland for the 2024 Swiss Nanoscience Institute’s Annual Meeting. For the second time, the meeting was held on the banks of lake Hallwil at the Hotel Seerose. Lukas and Luca both presented posters and Prof. Poggio hosted the proceedings in his role as SNI director.

New Group Members

Two new members recently started work in our group. Mirco Schwarz, who did his Masters Project in our lab, decided to continue working in the group and pursue his Masters degree with us. Mirco earned his Bachelor of Science in Physics in 2023 from the University of Basel and his project will focus on the mechanical properties of 2D magnetic materials. Dr. Damien Richert started work as a post-doctoral researcher in our group in the 2nd. Damien earned his Bachelors in Engineering from the Polytechnic Institute Clermont-Ferrand in 2014. He then went to Prof. Michael Santos’ group at the University of Oklahoma to work on III-V heterostructure characterization, earning his Masters in 2019. From 2021 to 2024, he worked at the Laboratoire National de Metrologie et d’Essais (LNE) under Dr. Francois Piquemal and Prof. Brice Gautier. There he earned his Ph.D. from the University of Lyon in 2024. In our group, he will concentrate on imaging of superconducting devices designed for quantum computing. Welcome to both Mirco and Damien!