Spin-dependent transport in cobalt nanocontacts
Spin-dependent transport in cobalt nanocontacts
The effect of an external magnetic field on the electronic transport in ferromagnetic materials - the magnetoresistance (MR) - is a physical effect of fundamental and industrial interest. Magnetic memory devices are used to store data by magnetic hysteresis and magnetic field sensors are used to rea...
| Personal Name(s): | Sarau, George (Corresponding author) |
|---|---|
| Contributing Institute: |
Elektronische Eigenschaften; IFF-9 Publikationen vor 2000; PRE-2000; Retrocat |
| Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2007
|
| Physical Description: |
90 S. |
| Dissertation Note: |
Universtität Duisburg-Essen, Campus Duisburg, Diss., 2006 |
| ISBN: |
3-89336-505-2 978-3-89336-505-0 |
| Document Type: |
Book |
| Research Program: |
ohne Topic |
| Series Title: |
Schriften des Forschungszentrums Jülich. Reihe Informationstechnik / Information Technology
18 |
| Subject (ZB): | |
| Link: |
OpenAccess |
| Publikationsportal JuSER |
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The effect of an external magnetic field on the electronic transport in ferromagnetic materials - the magnetoresistance (MR) - is a physical effect of fundamental and industrial interest. Magnetic memory devices are used to store data by magnetic hysteresis and magnetic field sensors are used to read data by magnetoresistance effects. The oldest known MR effect, discovered in 1857 by W. Thomson, is the anisotropic magnetoresistance (AMR), which results from spin-orbit scattering and is manifested as the resistance variation with the angle between the local magnetization and electrical current lines. The AMR effect in thin films was exploited in first magnetoresitive read heads for magnetic hard disk drives in 1992, resulting in an increase of the annual growth rate of the storage density from 25% to 60%. A giant magnetoresistance effect (GMR) was discovered in 1988 by P. Grünberg and A. Fert [1, 2] in systems consisting of two magnetic layers separated by a thin spacer layer a few nm thick. The resistance is usually lower when the magnetizations in the two ferromagnetic layers are parallel than in the anti-parallel case. This discovery had a great impact both through its industrial applications as read-heads, enabling the storage density to be increased at a 100% rate per year, and Magnetic Random Access Memories (MRAM), as well as for triggering the field of spintronics (SPIN elecTRONICS), aiming to use the spin of the charge carriers in electronic devices with enhanced functionalities. The integration of AMR and GMR read heads into the computer technology have helped to increase the arial density of magnetic disk drive by a factor of 35 millions, since the introduction of the first disk drive (RAMAC) in 1957 by IBM. This development was possible by decreasing the size of the magnetic grains that make up data bits and increasing the read head sensitivity (AMR - few percent, GMR - 65% [3]) along with a decrease in its size. Another magnetic device is the magnetic tunnel junction (MTJ), which is currently slowly replacing GMR read heads and has potential use in high speed, high density and nonvolatility MRAM. It consists of two ferromagnetic metals separated by [...] |