Magnetooptical properties of ferrimagnetic CoCr2S4in the near infrared

CoCr2S4, which is a ferrimagnetic insulator, has been prepared by hot-pressing microcrystalline powder. The infrared magneto-reflectance effects have been measured at several temperatures below the transition temperature of 221K. Very large Kerr effects, which are centered at 1.0 and 1.7 μm, have been associated with the principal crystal field transitions of divalent cobalt. These samples exhibit a normal remanence of at least 95 percent, which is attributed to strain-induced anisotropy in the sample. The transmission and Faraday rotation of the material are deduced from Kramers-Kronig and other analysis of the reflectance data. The use of this material in a digital-storage application is discussed