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Magnetic dipole and higher pole interaction on a square lattice
Melanie Ewerlin1, Derya Demirbas, Frank Brüssing
1Institut für Experimentalphysik/Festkörperphysik, Fakultät für Physik and Astronomie, Ruhr-Universität Bochum, Bochum 44780, Germany.
Physical Review Letters
|May 18, 2013
Summary
Researchers investigated magnetic interactions in patterned palladium-iron (PdFe) islands. Below 160 K, these islands form correlated chains, altering magnetic properties like coercivity and anisotropy.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Studying magnetic interactions in nanoscale materials is crucial for developing advanced magnetic storage and spintronic devices.
- Understanding the behavior of magnetic islands on patterned substrates provides insights into collective magnetic phenomena.
Purpose of the Study:
- To investigate the magnetic interaction and correlation between lithographically prepared circular magnetic islands on a square lattice.
- To characterize the magnetic properties and structural evolution of palladium-iron (PdFe) islands as a function of temperature.
Main Methods:
- Fabrication of polycrystalline PdFe islands (150 nm diameter, 300 nm periodicity) using lithography.
- Magnetic characterization through hysteresis loop measurements.
- Analysis of magnetic island correlation and chain formation using photoemission electron microscopy (PEEM) with circularly polarized X-rays at the Fe L3 edge.
Main Results:
- Below the Curie temperature (260 K), PdFe islands exhibit isotropic in-plane magnetization.
- Below 160 K, interisland interactions emerge, leading to changes in hysteresis shape, increased coercivity, and development of in-plane anisotropy.
- PEEM confirmed the formation of correlated elongated chains of magnetic islands, consistent with theoretical predictions of higher-order pole interactions.
- Neighboring chains were observed to orient irregularly, either parallel or antiparallel.
Conclusions:
- Interisland magnetic interactions significantly influence the magnetic properties of patterned PdFe islands at low temperatures.
- The formation of correlated magnetic chains is a key phenomenon driven by magnetic interactions beyond simple dipolar contributions.
- Experimental findings support theoretical models predicting complex magnetic ordering in arrays of magnetic nanostructures.
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