EventsDr. Alan Farhan

Artificial Frustrated Systems: Ongoing Research and Future Perspectives

Frustrated magnetism offers a variety of lattice geometries where interactions between magnetic moments cannot be simultaneously satisfied. Pyrochlore spin ice provided a prototypical example of the consequences of geometrical frustration with a highly debated zero-point entropy, which was successfully described using the concept of emergent magnetic charges . Artificial spin ice , consisting of dipolar coupled Ising-type nanomagnets, lithographically arranged onto a two-dimensional square lattice, was introduced as a two-dimensional analogue to pyrochlore spin ice and provided the prospect to microscopic studies on the consequence of geometrical frustration. In my presentation, I will intend to provide an overview on the evolution of artificial spin ice systems, starting from studies on the two classical cases of artificial square ice and artificial kagome spin ice to studies on novel concepts of artificial spin ice system. I will show how creative designs might pave the way to create systems where geometrical frustration can be directly tuned at the nanoscale. Synchrotron-based microcscopy techniques are then used to directly visualize thermal fluctuations and ordering phenomena in these systems. I will put these results in the context of currently undergoing research in the community and potential future directions.


About The Speaker


Dr. Farhan received his PhD degree in Physics from the University of Basel, Switzerland under the supervision of Prof. Laura Jane Heyderman. The focus of his PhD project aimed at the fabrication and investigation of so-called artificial spin ice systems that would exhibit thermal fluctuations. His thesis work marked a pioneering achievement in this field of research, with various research groups aiming to perform similar studies, using the same methods. Following his PhD graduation in August 2014 and short-term Postdoctoral stint at the ETH Zurich, Dr. Farhan received a Mobility fellowship from the Swiss National Science Foundation, allowing him to perform independent research on novel artificial spin systems at the Advanced Light Source, Lawrence Berkeley National Laboratory. These new studies revealed the possibility to design novel concepts of geomentrically frustrated spin systems, exhibiting exotic emergent phenomena that do not necessarily appear in nature. Since December 2017, taking advantage of a “Return” fellowship, Dr. Farhan returned back to Paul Scherrer Institute focusing on synchrotron-based studies on oxide thin films and magnetoelectric multiferroics.