Nicola Spaldin is the professor of materials theory at ETH Zurich. She developed the class of materials known as multiferroics, which combine simultaneous ferromagnetism and ferroelectricity, for which she received the 2017 L'Oréal-UNESCO For Women in Science award, among many other honors. She is a passionate science educator, director of her department’s study program, and holder of the ETH Golden Owl Award for excellence in teaching. When not trying to make a room-temperature superconductor, she can be found playing her clarinet, or skiing or climbing in the Alps. ABSTRACT: The behavior of the early early universe just after the Big Bang is one of the most intriguing basic questions in all of science, and is extraordinarily difficult to answer because of insurmountable issues associated with replaying the Big Bang in the laboratory. One route to the answer -- which lies at the intersection between cosmology and materials physics -- is to use laboratory materials to test the so-called "Kibble-Zurek" scaling laws proposed for the formation of defects such as cosmic strings in the early universe. Here I will show that a popular multiferroic material -- with its coexisting magnetic, ferroelectric and structural phase transitions -- generates the crystallographic equivalent of cosmic strings. I will describe how straightforward solution of the Schroedinger equation for the material allows the important features of its behavior to be identified and quantified, and present experimental results of what seem to be the first unambiguous demonstration of Kibble-Zurek scaling in real materials. I will end with some very recent data showing that cosmic strings in multiferroics might be less unambiguous than they seem... The Colloquium will be livestreamed at: ictp.it/livestream. Light refreshments will be served after the event. All are welcome to attend.
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