Experimental Magnetic Imaging Study of Novel States on Artificial Spin Ice Systems
Date of Award
Doctor of Philosophy (PhD)
Artificial spin ice systems are two dimensional arrays of magnetic nanoislands that are designed to study the collective behavior of frustrated systems. Each nanoisland possesses a discrete magnetic moment and the interactions between moments can be controlled by modifying the nanoislands’ shape, lateral dimensions, and geometrical arrangement. This thesis focuses on the novel states of different ASI systems and probe the magnetic configurations using a variety of imaging techniques. The first step is to access the ground states through an annealing treatment. We optimize the annealing protocol using the square ice lattice. The annealing study is then extended to examine the ground state of Santa Fe Ice lattice, whose magnetic configuration can be described under an emergent string framework. We also measure the thermally active process Santa Fe lattice and analyze the dynamics process through string kinetics. Finally, we utilize the annealing protocol to study the low energy state of the tripole lattice, in which each nano-island has three equilateral arms and six degrees of freedom in moment directions. All these studies manifest the existence of novel states and their emergent behaviors in ASI systems.
Zhang, Xiaoyu, "Experimental Magnetic Imaging Study of Novel States on Artificial Spin Ice Systems" (2022). Yale Graduate School of Arts and Sciences Dissertations. 544.