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Nanoscale Josephson Devices 10.17863/CAM.14186 Bell, Chris This thesis describes the development and applications of sub-micron current-perpendicular-toplane devices fabricated by three-dimensional etching with a focused ion beam microscope. This technique was applied to a range of materials, including the study of c-axis Josephson junctions in the high temperature superconductor Tl2Ba2CaCu2O8, the fabrication of superconducting quantum interference devices with sub-micron loop areas, and GaN light emitting diodes. The main body of research was carried out in the study of Nb based Josephson junctions working at a temperature of 4.2 K. Junctions with normal metal, insulating and ferromagnetic barriers were characterised, as well as the first metallic antiferromagnetic Josephson junctions using γ-Fe50Mn50 as the barrier. ‘Pseudo-spin-valve’ Josephson junctions were also created using a Co/Cu/Fe20Ni80 barrier. In this case the relative orientation of the magnetic moments of the Co and Fe20Ni80 could be changed with an applied magnetic field. The magnetoresistance and critical current of the device showed a strong correlation, implying a direct influence of the magnetic structure of the device on the critical current. University of Cambridge 2003-12 Thesis Doctoral Doctor of Philosophy (PhD) en http://www.dspace.cam.ac.uk/handle/1810/34607 https://www.repository.cam.ac.uk/handle/1810/34607 https://www.repository.cam.ac.uk/bitstreams/5c1e49f9-cd58-4eed-bd3a-d304e8fc6543/download a7616f7d3eb87d6b6d7f8d54553a00fd https://www.repository.cam.ac.uk/bitstreams/5b012f4a-cd18-4475-aeb2-e9f560b8388b/download d5cde899edba7dd85fbf81ca41e9b671 https://www.repository.cam.ac.uk/bitstreams/93923cb0-d82a-4732-adfe-46ed380c82c2/download c2b3ad242a106e8509a6ef22a9d1e22a https://www.repository.cam.ac.uk/bitstreams/4f60745c-740d-421c-b144-3fe75c0bf1a7/download 50ef09617fa7b4b7a8981d5a724a480b https://www.rioxx.net/licenses/all-rights-reserved/ Nanoscale Devices Josephson Junctions