Magnetic and magneto-optical properties of a cerium YIG single crystal

The magnetization and 1.15 μm wavelength Faraday rotation of Ce
x
Y
3-x
Fe
5
O
12
(Ce
x
= YIG) with x = 0.06 single crystals have been measured. For two directions of the applied magnetic field (H [111] and H [110]) up to 50 kOe, the isothermal magnetization curves are identical to that of pure YIG between 4.2 and 300 K. On the other hand, the Faraday rotation (F.R.) in a maximum field of 20 kOe parallel to the [111] direction is always negative (with respect to the positive FR of YIG) and strongly enhanced when the temperature is lowered from 300 to 77 K. These interesting magnetooptical properties are associated to the presence of Ce
³⁺
ions in the samples.