Features of the Faraday effect in the rare earth orthoaluminate DyAlO$_3$

The magnetic susceptibility and the Faraday effect in DyAlO$_3$ single crystal samples are studied in the temperature range of 78–300 K along the easy-magnetization axis b of the orthorhombic crystal. The studies are supplemented with similar investigations of terbium orthoaluminate TbAlO$_3$. The Faraday rotation and the natural birefringence typical for crystals of the orthorhombic syngony are found from the temperature and spectral dependences of the rotation angles $\Theta$ of the major axis of the light polarization ellipse measured in the wavelength range of 440–750 nm. The linearity of the dependence of the Verdet constant $V$ on the magnetic susceptibility $\chi$ of the DyAlO$_3$ crystal at a wavelength of 506 nm allowed calculation of the paramagnetic Verdet constant $C_p$ of DyAlO$_3$. The $C_p$ constants and the effective frequencies $\omega_0$ of allowed transitions found in rare-earth RAlG garnets (R = Tb$^{3+}$, Dy$^{3+}$) are compared with the corresponding values determined in RAlO$_3$ crystals. The possibility of practical application of RAlO$_3$ crystals studied in this work is briefly discussed.