Submicron structures 26 th January 2004 msc Condensed Matter Physics Photolithography to ~1 μm Used for... Spin injection Flux line dynamics Josephson junctions SQUIDs Superconducting mesa structures features to 1-2 μm Device Physics cleanroom

Submicron structures 26 th January 2004 msc Condensed Matter Physics Opportunities below 1 μm Higher interface resistance R simplifies interpretation. Get R > h/e 2 : resistance quantum Measure spin flip length < 1 μm Isolate individual crystal grains/twins: directions important for d-wave superconductors Access mesoscopic quantum behaviour: single electron, single spin, single Cooper pair dd 300 nm I

Submicron structures 26 th January 2004 msc Condensed Matter Physics Focused Ion Beam fabrication 30 kV Ga ion source Focus to ~30 nm. Remove or add material Observe by SEM while writing, select desired region of sample University Nanotechnology Research Centre (Mechanical Engineering)

Submicron structures 26 th January 2004 msc Condensed Matter Physics Superconducting wires to 100 nm (so far...) by FIB Well-controlled structure Quantum effects easily seen 6 μm photolith. 270 nm FIB Superconducting phase slip

Submicron structures 26 th January 2004 msc Condensed Matter Physics Physics << 1 μm Use quantum effects as a probe of electron systems – e.g. Coulomb blockade to measure energy distribution Quantum computers motivate study of systems having quantum coherence Combine mesoscopic conductors with intrinsic Josephson tunnelling

Submicron structures 26 th January 2004 msc Condensed Matter Physics Our strengths Expertise in ultrasensitive electrical measurements: - Shot noise - SQUID detectors Well-equipped for quantum-dominated measurements: - mK temperatures - 10 T fields Wide range of interesting material properties - HTc have energy gap > kT & charging energy - HTS have nm-scale laminar structure - Ferromagnetic, unconventional materials available

Submicron structures 26 th January 2004 msc Condensed Matter Physics