Einfluß der magnetischen Dipolkopplung auf den Tunnelmagnetowiderstand in Schichtsystemen und strukturierten Elementen

We have studied the effect of the dipolar magnetic coupling (also known as Néel coupling or "orange-peel" coupling) in tunneling magnetoresistive (TMR) elements. With an in situ scanning tunneling microscope we directly accessed the roughness of the films and found a close correspondence between the values for the coupling fields determined by the magneto-optical Kerr effect and the ones computed on the basis of the measured morphology parameters. We confirm an increase of the dipole coupling between magnetic layers with decreasing barrier thickness as predicted by the model. Deviations from the theoretical predictions are observed for the case of thinner soft magnetic layers, which can be explained by reduced magnetisation in very thin films. We demonstrate the importance of dipolar coupling for understanding the magnetic behaviour of TMR elements by comparing TMR curves for optimised and nonoptimised structures.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Technische Universität Dresden

Year

2001

Author dc:creator

• Tegen, Stefan

Contributors dc:contributor

• Fink, Jörg
• Laubschat, Clemens
• Reiss, Günther

• Magnetismus
• Rauhigkeit
• Schichtsysteme
• TMR
• magnetische Dipolkopplung
• dipolar magnetic coupling
• layer systems
• magnetism
• roughness