March 2011

Abstracts of the QSIT Lunch Seminar, March 3, 2011

Multistage Zeeman Deceleration of Metastable Neon

Michael Motsch, Laboratory of Physical Chemistry, ETH Zurich

Multistage Zeeman deceleration exploits the interaction between paramagnetic atoms or molecules and pulsed magnetic fields to slow a supersonic beam of these particles in a phase-stable manner. We start by exciting Ne atoms to the metastable 3P2 state with a DC discharge in the expansion region behind a pulsed gas nozzle. Using 91 deceleration solenoids, we slow Ne* atoms to velocities as low as 120m/s, thereby removing up to 95% of the initial kinetic energy. We characterize the cold sample of Ne* atoms with a time-of-flight technique, investigate the efficiency of the deceleration process, and discuss the possibility to extend the technique to other species.

Ferromagnetic contacts for carbon nanotube spintronic devices

Hagen Aurich, Nanoelectronics Group, University of Basel

One of the most fundamental spintronics structures is the spin-valve consisting of two ferromagnetic layers coupled to a non-magnetic structure in-between. The presentation gives an introduction to spin-valves, focusing on lateral devices with carbon nanotube (CNT) quantum dots (QDs) as coupling medium. CNTs are ideal because of their low spin-orbit coupling and the wealth of nanoelectronics phenomena they offer. In particular, they allow to tune the magneto resistance by electrically tuning the QD states. We demonstrate that Permalloy (NiFe), the standard material in nanomagnetism experiments, is a well-suited material to contact CNT spintronics devices, i.e. Permalloy contacts show the required magnetic properties and couple well to the CNT.

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