Physical Sciences and Mathematics Commons^™

Nanoscale Studies Of The Ferroelectric And Electromechanical Properties Of Hafnia-Based Capacitors, Pratyush Buragohain

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

The work presented in this dissertation aims to provide nanoscopic insights into the electrical and electromechanical behavior of the recently discovered ferroelectric HfO₂ or hafnia-based capacitors. Hafnia-based ferroelectrics are highly promising for technological applications due to compatibility with the existing Si technology. To realize the full potential of hafnia, however, requires comprehensive understanding of its properties. In this regard, this dissertation hopes to bridge a gap between an understanding of the nanoscopic and macroscopic properties of hafnia by performing combined high-resolution piezoresponse force microscopy (PFM) and pulse switching studies.

More specifically, the dynamics of domain nucleation and wall motion …

Magnetism Of Novel Rare-Earth-Free Intermetallic Compounds, Haohan Wang

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Rare-earth-free magnets have drawn lots of interest because of their low cost, and the production is not limited by the shortage of rare-earth elements. This dissertation focuses on three rare-earth-free materials, Fe-Co-Ti alloys, Fe-Ni-B alloys, and Co-Si. All of them are synthesized by arc melting followed by melt-spinning. Fe_3+xCo_3−xTi₂ (x = 0, 2, 3) alloys exhibit hexagonal crystal structures and show non-collinear spin structures according to neutron diffraction. The magnetic moments have projections on both the c-axis and basal plane, and the corresponding misalignment angle exhibits a nonlinear decrease with …