Interference induced enhancement of magneto-optical Kerr effect in ultrathin magnetic films

Abstract

We have studied the magneto-optical spectra of ultrathin magnetic films deposited on Si substrates coated with an oxide layer (SiOx). We find that the Kerr rotation angle and the ellipticity of ~1 nm thick CoFeB thin films, almost transparent to visible light, show a strong dependence on the thickness of the SiOx layer. The Kerr signal from the 1 nm CoFeB thin film can be larger than that of ~100 nm thick CoFeB films for a given SiOx thickness and light wavelength. The enhancement of the Kerr signal occurs when optical interference takes place within the SiOx layer. Interestingly, under such resonance condition, the measured Kerr signal is in some cases larger than the estimation despite the good agreement of the measured and calculated reflection amplitude. We infer the discrepancy originates from interface states that are distinct from the bulk characteristics. These results show that optical interference effect can be utilized to study the magneto-optical properties of ultrathin films.

References in corpus (11)

• Layer-dependent Ferromagnetism in a van der Waals Crystal down to the Monolayer Limit
• Discovery of intrinsic ferromagnetism in 2D van der Waals crystals
• Spin torque switching with the giant spin Hall effect of tantalum
• New Perspectives for Rashba Spin-Orbit Coupling
• Current-driven dynamics of chiral ferromagnetic domain walls
• Making graphene visible
• Symmetry and magnitude of spin-orbit torques in ferromagnetic heterostructures
• Layer thickness dependence of the current induced effective field vector in Ta|CoFeB|MgO
• Domain wall motion governed by the spin Hall effect
• Interface control of the magnetic chirality in CoFeB|MgO heterosctructures with heavy metal underlayers
• Asymmetric Magnetic Domain-Wall Motion by the Dzyaloshinskii-Moriya Interaction

Cited by in corpus (4)

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• Enhancing magneto-optic effects in two-dimensional magnets by thin-film interference
• Optical detection of spin orbit torque and current induced heating
• Polar and quadratic magneto-optical Kerr effects in nonmagnetic/ferromagnet bilayers for spin-orbit torque measurements