High precision magnetic linear dichroism measurements in (Ga,Mn)As

Area of Science:

• Condensed matter physics
• Materials science
• Optics

Background:

• First-order magneto-optical Kerr effects (MOKEs) are widely used for magnetic material investigation.
• Second-order (quadratic) magneto-optical (MO) effects are rarely utilized due to small signal magnitudes and difficulty in separating them from artifacts.
• A giant quadratic MO effect, magnetic linear dichroism (MLD), was discovered in (Ga,Mn)As in 2005.

Purpose of the Study:

• To compare four experimental techniques for measuring MLD and distinguishing it from artifacts.
• To establish a reliable method for measuring second-order MO effects.
• To investigate the MLD spectra of (Ga,Mn)As.

Main Methods:

• Comparison of four distinct experimental techniques for MLD measurement.
• Utilizing polarization monitoring of reflected light.
• Rotating sample magnetization with an external magnetic field to separate signals.

Main Results:

• The most reliable MLD measurements are achieved by monitoring reflected light polarization during magnetization rotation.
• MLD spectra of (Ga,Mn)As were measured across a broad spectral range (0.1 eV to 2.7 eV).
• MLD was found to have a magnitude comparable to polar MOKE signals in (Ga,Mn)As.

Conclusions:

• Monitoring reflected light polarization during magnetization rotation is a robust method for measuring MLD.
• This technique facilitates the study of in-plane magnetization dynamics in materials like (Ga,Mn)As.
• Second-order MO effects, like MLD, offer valuable insights comparable to established first-order effects.