Magneto-optic properties of uranium-based compounds

Uranium‐based compounds often show interesting magnetic properties and large polar Kerr rotations. Because of this, the wavelength and temperature dependencies of the polar Kerr rotation in several uranium‐based compounds, including UMn2Ge2, UFe2, and UGa2, have been investigated. The Mn moments order ferromagnetically in UMn2Ge2 below 380 K, and while the U moments do not order ferromagnetically until the temperature is below 150 K. The measurements presented here show that the size of the Kerr rotation increases from 0.05° at room temperature to 0.15° when the U moments are ordered. The wavelength dependence of the Kerr rotation between 500 and 1000 nm is rather weak. UGa2 orders ferromagnetically at 130 K, and a Kerr rotation of 0.2° at 85 K and 632.8 nm can be measured, with the rotation increasing to 0.4° at 1000 nm. UFe2 orders ferromagnetically at 180 K, and the Kerr rotation (85 K, 632.8 nm) is 0.17°. These magnetic and optical properties are discussed in terms of the electronic states of uranium.