Quadratic magnetooptic spectroscopy setup based on photoelastic light modulation

Abstract

In most of the cases the magnetooptic Kerr effect (MOKE) techniques rely solely on the effects linear in magnetization ($\mathbf{M}$). Nevertheless, a higher-order term being proportional to $\mathbf{M}$${}^2$ and called quadratic MOKE (QMOKE) can additionally contribute to experimental data. Handling and understanding the underlying origin of QMOKE could be the key to utilize this effect for investigation of antiferromagnetic materials in the future due to their vanishing first order MOKE contribution. Also, better understanding of QMOKE and hence better understanding of magnetooptic (MO) effects in general is very valuable, as the MO effect is very much employed in research of ferro- and ferrimagnetic materials. Therefore, we present our QMOKE and longitudinal MOKE spectroscopy setup with a spectral range of 0.8--5.5\,eV. The setup is based on light modulation through a photoelastic modulator and detection of second-harmonic intensity by a lock-in amplifier. To measure the Kerr ellipticity an achromatic compensator is used within the setup, whereas without it Kerr rotation is measured. The separation of QMOKE spectra directly from the measured data is based on measurements with multiple magnetization directions. So far the QMOKE separation algorithm is developed and tested for but not limited to cubic (001) oriented samples. The QMOKE spectra yielded by our setup arise from two quadratic MO parameters $G_s$ and $2G_{44}$, being elements of quadratic MO tensor $\mathbf{G}$, which describe perturbation of the permittivity tensor in the second order in $\mathbf{M}$.

7 pages, 5 figures

References in corpus (6)

• Optical determination of the Neel vector in a CuMnAs thin-film antiferromagnet
• Huge quadratic magneto-optical Kerr effect and magnetization reversal in the Co${}_2$FeSi Heusler compound
• Thickness dependence of linear and quadratic magneto-optical Kerr effect in ultrathin Fe(001) films
• Comparative Study of Optical and Magneto-Optical Properties of Normal, Disordered and Inverse Spinel Type Oxides
• Separation of the first- and second-order contributions in magneto-optic Kerr effect magnetometry of epitaxial FeMn/NiFe bilayers
• Quadratic-in-magnetization permittivity and conductivity tensor in cubic crystals

Cited by in corpus (6)

• Quadratic magnetooptic Kerr effect spectroscopy of Fe epitaxial films on MgO(001) substrates
• Laser-driven first-order spin reorientation and Verwey phase transitions in the magnetite Fe${}_3$O${}_4$ beyond the range of thermodynamic equilibrium
• Scaling of quadratic and linear magnetooptic Kerr effect spectra with L2${}_1$ ordering of Co${}_2$MnSi Heusler compound
• Cubic magneto-optic Kerr effect in Ni(111) thin films with and without twinning
• Cubic magneto-optic Kerr effect in Co(111) thin films
• Cubic-in-magnetization contributions to the magneto-optic Kerr effect investigated for Ni(001) and Ni(111) thin films