Angular Characterization of Magneto Optical Kerr-Effect by Ellipticity Modulation in Ultrathin Samples

Magnetism in 2D materials has become of paramount interest in the scientific community because of overcoming the limitations of the Mermin-Wagner theory, nevertheless, new puzzling questions have arisen. Establishing the thickness frontier between bulk ferromagnetism and few-layer antiferromagnetism or the determination of the spin model that the 2D magnets follow are some of the current unsolved questions. One of the most sensitive techniques for characterizing the magnetism is the polarization changes of ellipticity-modulated light when interacts with a magnetic material. This technique permits to characterize both the Kerr-rotation and magneto-circular dichroism with a sensitivity bellow 100 µrad. Here, we will show the peculiarities of the experiments and simulations of the angular response of Van der Waalls magnetic materials. In particular, the Fourier plane response is acquired and compared with the simulation of the magneto-optical behavior. The fit results could allow extracting important parameters such as the spin orientation.