Electronic Theory for the Nonlinear Magneto-Optical Response of Transition-Metals at Surfaces and Interfaces: Dependence of the Kerr-Rotation on Polarization and on the Magnetic Easy Axis

We have performed a systematic magneto-optical Kerr spectroscopy study of GaMnAs with varying Mn densities as a function of temperature, magnetic field, and photon energy. Unlike previous studies, the magnetization easy axis was perpendicular to the sample surface, allowing us to take remanent polar Kerr spectra in the absence of an external magnetic field. The remanent Kerr angle strongly depended on the photon energy, exhibiting a large positive peak at $\sim1.7$ eV. This p...

We compute the nonlinear optical response of an Fe monolayer placed on top of 1 to 4 monolayers of Cu(001). Our calculation is based on ab initio eigenstates of the slab, which are obtained within the full-potential linearized augmented plane-wave method. The ground-state spin-polarized electronic structure is converged self-consistently to an accuracy better than 0.1 mRy. Subsequently, we take the spin-orbit interaction into account within a second variational treatment. The...

In the present work, spin orientation and variation of the strength of coupling in [Co/Pt]ML/Fe multilayer have been investigated as a function of the thickness of the Fe layer. [Co/Pt]ML/Fe multilayer has orthogonal anisotropy with the Fe layer, and [Co/Pt]ML has in-plane magnetic anisotropy and perpendicular anisotropy, respectively. Measurements are performed using in-situ magneto-optical Kerr effect (MOKE) and isotope-sensitive depth-resolved nuclear resonance scattering ...

The Magneto-Optical Kerr Effect (MOKE) is a fundamental tool in magnetometry, pivotal for advancing research in optics, magnetism, and spintronics as a direct probe of magnetization. Traditional MOKE measurements primarily detect the magnetization components parallel to the Poynting vector, which can only access the magnitude but not the direction of the orthogonal component. In this study, we introduce an orthogonal MOKE geometry in which the Kerr signal detects both the mag...

A large nonlinear magneto-optical effect is observed in a non-centrosymmetric Fe/AlGaAs (001) heterostructure. This effect is a direct consequence of interference between second-harmonic optical waves of magnetic and crystallographic origin, generated at ferromagnetic Fe interface and bulk AlGaAs, respectively. The longitudinal nonlinear Kerr rotation is measured to be 1.6 degrees along the [1-10] hard axis, about two orders of magnitude stronger than the linear equivalent. T...

We describe a simple magneto-optical experiment and introduce a magneto-optical Kramers-Kronig analysis (MOKKA) that together allow extracting the complex dielectric function for left- and right-handed circular polarizations in a broad range of frequencies without actually generating circularly polarized light. The experiment consists of measuring reflectivity and Kerr rotation, or alternatively transmission and Faraday rotation, at normal incidence using only standard broadb...

Magneto-optical effects have been investigated over the infrared{visible spectral range in ACr2O4 (A = Fe, Co) spinel oxides with non-collinear spin orders in their ground states. We found large magneto-optical Kerr rotation and ellipticity at the on-site d-d transitions of the A2+ ions located within the charge gap. The magneto-optical Kerr rotation of 12 deg observed in CoCr2O4 is unprecedentedly large among magnetic semiconductors and points towards the uniqueness of tetra...

The contour integration technique applied to calculate the optical conductivity tensor at finite temperatures in the case of inhomogeneous surface layered systems within the framework of the spin-polarized relativistic screened Korringa-Kohn-Rostoker band structure method is extended to arbitrary polarizations of the electric field. It is shown that besides the inter-band contribution, the contour integration technique also accounts for the intra-band contribution too. Introd...

The interplay of light and magnetism has been a topic of interest since the original observations of Faraday and Kerr where magnetic materials affect the light polarization. While these effects have historically been exploited to use light as a probe of magnetic materials there is increasing research on using polarized light to alter or manipulate magnetism. For instance deterministic magnetic switching without any applied magnetic fields using laser pulses of the circular po...

Ultra-thin magnetic dielectric films are of prime importance due to their applications for nanophotonics and spintronics. Here, we propose an efficient method for the magneto-optical investigation of ultra-thin magnetic films which allows one to access their state of magnetization and magneto-optical properties. It is based on the surface-plasmon-polariton-assisted transverse magneto-optical Kerr effect (TMOKE). In our experiments, sub-100 nm-thick bismuth-substituted lutetiu...