LARGE ROOM-TEMPERATURE MAGNETOOPTICAL KERR EFFECT IN CUCR2SE4-XBRX (X = 0 AND 0.3)

The reflectivity between 0.03 and 12.4 eV and the magneto-optical polar Kerr rotation and Kerr ellipticity between 0.55 and 5.17 eV have been measured on CuCr2Se4-xBrx with x = 0 and 0.3. In the infrared large Kerr effects up to -1.19-degrees at room temperature have been observed. The origin of these effects is a strong interband transition, probably a charge transfer transition, which is additionally enhanced by a plasma edge in the reflectivity. It is shown that the energy of the maximum Kerr effect can be tuned by suitable substitutions.