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Manipulating Magnetic Vortices in Permalloy/YBCO Hybrid Structures for High-Density Data Storage

thesis
posted on 2025-05-26, 06:37 authored by Cankut Eker

Magnetic vortices in Permalloy microdots integrated with Yttrium Barium Copper Oxide (YBCO) thin films exhibit unique magnetic properties that hold potential for memory storage applications and superconducting device performance. Advanced fabrication techniques, including pulsed laser deposition for YBCO films and photolithography for Permalloy microdots, have been optimised to achieve high-quality samples. Characterisation through scanning electron microscopy, atomic force microscopy, and magnetic force microscopy highlights the influence of deposition parameters on film quality and microdot formation, revealing the need for refined fabrication processes to minimise surface defects and stabilise vortex states.

Magnetoresistance measurements and nanoSQUID simulations, based on the Time-Dependent Ginzburg-Landau model, indicate that the polarity of magnetic vortices can be effectively detected and controlled, demonstrating the feasibility of utilising these systems for nonvolatile data storage. The integration of nanoSQUID technology allows for the direct observation of magnetic vortex dynamics, suggesting the capability to encode information using the magnetic vortex polarity with minimal power consumption.

Further exploration of non-uniform antidot arrays embedded in YBCO films reveals enhanced Abrikosov vortex pinning and asymmetric vortex mobility, indicating a ratchet effect. Triangular antidot geometries exhibit the strongest ratchet behaviour, potentially serving as Abrikosov vortex diodes to manage flux motion and improve signal-to-noise ratios in superconducting devices. Uniform arrays show robust pinning capabilities, whereas graded arrays introduce tunable ratchet-like behaviours, offering a versatile approach for designing high-performance superconducting systems. The simulations align closely with experimental observations, providing a theoretical foundation for the development of advanced superconducting vortex-based electronic and quantum devices.

These findings advance the understanding of magnetic vortex behaviour in hybrid Permalloy/YBCO superconducting structures, providing a solid foundation for future research in magnetic storage technologies. Further, the versatility and unique properties of magnetic vortices extend their utility beyond traditional data storage, offering potential applications in high-resolution imaging, quantum sensing, neural stimulation, and biomedicine. This highlights the diverse capabilities of vortex states and their role in the advancement of technologies across multiple disciplines.

History

Year

2025

Thesis type

  • Doctoral thesis

Faculty/School

School of Physics

Language

English

Disclaimer

Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.

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