Orange Peel coupling in granular ferromagnetic films

TL;DR

This paper investigates the orange peel coupling effect in granular ferromagnetic films within magnetic tunnel junctions, revealing a strong interaction influenced by grain size that affects magnetoresistance behavior.

Contribution

It demonstrates the presence of orange peel coupling in granular ferromagnetic films and quantifies its dependence on grain size, a novel insight into magnetic interactions in such structures.

Findings

Zero field resistance dip observed in MR measurements

Dip magnitude varies with grain size

Coupling strength exceeds that of continuous ferromagnetic layers

Abstract

We present magnetoresistance (MR) measurements performed on magnetic tunnel junctions in which one of the electrodes is a granular ferromagnetic film. These junctions exhibit a zero field resistance dip. The dip magnitude depends on the size of the grains. We interpret these results as a consequence of the orange peel effect between the continuous ferromagnetic film and the magnetic grains. The coupling is found to be much stronger than that between continuous ferromagnetic layers.