Magneto Optical Characterization of Artifical Spin Ice & Quasi Crystals

Artificial Spin Ices (ASI) are nanoscale dipole magnet configurations compiled in periodic arrangements and made of ferromagnetic materials. Artificial magnetic quasicrystals (AMQ) are similar to ASIs, but lack translational symmetry while retaining quasi-periodicity.   Research into ASIs and AMQs has been growing significantly due to emerging applications such as reservoir computing and studies of physical phenomena such as effective magnetic monopoles.  Here we study the magnetic reversal and hysteresis of three quasi-periodic systems realized in Ni0.8Fe0.2: (1) the square ASI with topological defects, (2) the monotile, or "einstein," AMQ, and (3) the Ammann-Beenker quasicrystal.  These systems are characterized using the magneto-optic Kerr effect (MOKE) to understand the dependence of the reversal processes on applied magnetic field, angle, and temperature.