Abstract-Terahertz magneto-optics in the ferromagnetic semiconductor HgCdCr2Se4

T. J. Huisman¹, R. V. Mikhaylovskiy¹, A. V. Telegin², Yu. P. Sukhorukov², A. B. Granovsky³, S. V. Naumov², Th. Rasing¹ and A. V. Kimel¹
http://scitation.aip.org/content/aip/journal/apl/106/13/10.1063/1.4916884
1 Institute for Molecules and Materials, Radboud University Nijmegen, 6525 AJ Nijmegen, The Netherlands
2 M. N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620990 Ekaterinburg, Russia
3 Department of Physics, M. V. Lomonosov Moscow State University, Moscow 119991, Russia
Appl. Phys. Lett. 106, 132411 (2015); http://dx.doi.org/10.1063/1.4916884

The magneto-optical response of the ferromagnetic semiconductor HgCdCr2Se4 at terahertz (THz) frequencies is studied using polarization sensitive THz time-domain spectroscopy. It is shown that the polarization state of broadband terahertz pulses, with a spectrum spanning from 0.2 THz to 2.2 THz, changes as an even function of the magnetization of the medium. Analysing the ellipticity and the rotation of the polarization of the THz radiation, we show that these effectsoriginate from linear birefringence and dichroism, respectively, induced by the magnetic ordering. These effects are rather strong and reach 10²rad/m at an applied field of 1 kG which saturates the magnetization of the sample. Our observation serves as a proof-of-principle showing strong effects of the magnetic order on the response of a medium to electric fields at THz frequencies. These experiments also suggest the feasibility of spin-dependent transport measurements on a sub-picosecond timescale.