Optical magnetoelectric effect in a submicron patterned magnet

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• The optical magnetoelectric effect is a phenomenon where light influences magnetic properties and vice versa.
• Investigating this effect in artificial magnetic superstructures can lead to novel optical and magnetic functionalities.
• Breaking both space inversion and time reversal symmetry is crucial for observing such effects.

Purpose of the Study:

• To demonstrate and characterize the optical magnetoelectric effect in a submicron patterned magnet.
• To explore the nonreciprocal directional dichroic response in visible and near-infrared light.
• To analyze the dependence on light polarization and applied magnetic field.

Main Methods:

• Fabrication of a submicron artificial magnetic superstructure using chevron-shaped permalloy (Ni80Fe20) islands on a silicon substrate.
• Monitoring the intensity of diffracted visible or near-infrared light.
• Analyzing the light-polarization angle and magnetic field (H) dependence of the diffracted intensity.

Main Results:

• Successful demonstration of the optical magnetoelectric effect in the patterned permalloy nanostructures.
• Observation of a finite change in diffracted light intensity (approximately 10^-3 at room temperature with H = 500 Oe).
• Comparison with submicron square patterns confirmed the effect's emergence in the chevron geometry.

Conclusions:

• The study confirms the presence of the optical magnetoelectric effect in a system where space and time symmetries are broken.
• The observed effect is linked to the specific geometry of the artificial magnetic superstructure.
• This finding opens possibilities for developing new magneto-optical devices and sensors.