Seminar of Physics of Wrocław University of Technology
PWr, bud. A1, sala 322
How to study magnetic monopoles (in Artificial Spin Ice)?
dr hab. Mateusz Goryca
Instytut Fizyki Doświadczalnej, Wydział Fizyki, Uniwersytet Warszawski
Magnetic monopoles are hypothetical particles that possess a single magnetic pole, either north or south, unlike common magnets that always have both poles combined. If they exist, magnetic monopoles would represent a fundamental departure from the current understanding of magnetism, and many of physics's grandest theories require single, freely moving magnetic poles. Despite extensive theoretical predictions, however, experimental evidence for their existence remains elusive. Fortunately, this does not prohibit the studies of magnetic monopoles, as certain solid-state systems exhibit monopole-like quasiparticles. Those non-elementary entities mimic the behavior of magnetic monopoles and can interact with each other and with applied magnetic fields via the magnetic analog of the electronic Coulomb interaction.
The seminar will focus on one of such solid-state systems that exhibit monopole-like fundamental excitations: arrays of interacting nanomagnets known as Artificial Spin Ices (ASIs). By using a novel technique of optical noise spectroscopy to passively "listen" to spontaneous magnetization fluctuations in ASI lattices, we unveil distinct phases rich in dense and highly mobile monopoles and study their kinetic properties. The discovery of such on-demand monopole regimes with tunable kinetic properties offers novel avenues for probing magnetic charge dynamics. In particular, it introduces a new paradigm for investigating magnetricity – the magnetic equivalent of electricity that uses magnetic "charges".
