2026-09-20T14:36:21Zhttps://cora.ucc.ie/server/oai/request

oai:cora.ucc.ie:10468/140952023-04-04T10:48:40Zcom_10468_388com_10468_5com_10468_129com_10468_224com_10468_1com_10468_41com_10468_6col_10468_389col_10468_581col_10468_430col_10468_8983col_10468_3619

embargoed 2028-05-31 McCloskey, Paul O Mathuna, Cian Masood, Ansar Cronin, Darragh Science Foundation Ireland 2023-01-18T12:25:52Z 2023-01-18T12:25:52Z 2022-11-01 2022-11-01 The past decades have seen a surge in demand for highly miniaturised magnetic components which has been enabled by use of power circuitry high switching frequencies which require energy storage on a smaller scale. The optimal scale of this integration will be achieved with the complete integration of the power supply onto silicon. Hence there is a demand for soft magnetic materials for power conversion applications in the high MHz frequency range. These materials should exhibit crucial properties such as a low coercivity, high saturation magnetisation and a high resistivity for optimum performance. Methods to further optimise the intrinsic qualities of an ultra-soft magnetic material, CoZrTaB (CZTB) are presented. This includes methods to maintain in-plane, uniaxial magnetic anisotropy as well as efforts to produce composite soft magnetic materials such as CoZrTaB-N\textsubscript{2} via methods such as reactive sputtering. Furthermore Spin-Reorientation Transition in amorphous CZTB magnetic multilayers is investigated. This interesting phenomenon results from from a tuneable value of residual stress arising from a thermal shock effect at elevated temperatures, shifting the magnetic anisotropy from in-plane to out-of-plane. This study highlighted how external parameters such as stress and thermal effects can damage properties such as uniaxial magnetic anisotropy, essential for specific applications. Work on a novel soft magnetic composite – CoZrTaB-SiO\textsubscript{2} is also presented. This study involved the technique of co-sputtering to produce a composite amorphous magnetic and non-magnetic microstructure, comprehensively examining all aspects of the material and its vital properties resulting in an ultra-soft magnetic material. Moreover, this material exhibited an increased and tuneable resistivity, dependant on sputtering conditions. Finally, a detailed and systematic experiment to develop a low footprint inductor consisting of a 3-D vertical array of vertical copper cylinders (or pillars) coated in CZTB multilayers. This novel structure was designed for a low-footprint with high inductance-density values. This work focused precisely on the magnetic laminations and the techniques used to ensure vital properties were retained such as a low coercivity and a circumferential magnetic hard axis to correspond with the current induced magnetic field. Not peer reviewed Accepted Version application/pdf Cronin, D. 2022. Thin film magnetics for integrated magnetic nano-structures. PhD Thesis, University College Cork. 197 https://hdl.handle.net/10468/14095 en University College Cork info:eu-repo/grantAgreement/SFI/SFI Investigator Programme/15/IA/3180/IE/Advanced Integrated Power Magnetics Technology- From Atoms to Systems/ © 2022, Darragh Cronin. https://creativecommons.org/licenses/by-nc-nd/4.0/ Magnetics Materials Science Physics Inductors Amorphous Nanocrystalline Magnetoelastic Magnetic materials Sputter deposition Magnetic anisotropy Thin films Thin film magnetics for integrated magnetic nano-structures Doctoral thesis Doctoral PhD - Doctor of Philosophyinfo:eu-repo/semantics/embargoedAccess