Faraday Rotation and Birefringence of Fe3BO6

The intrinsic Faraday rotation and birefringence of Fe3BO6 are measured in a wavelength range of 0.6∼0.7 µm; along the a axis below and along the c axis above the spin reorientation temperature. The birefringence is about three times as large as that of orthoferrite YFe1-x Co x/2Ti x/2O3. The Faraday rotation along the a axis is found to be 1.4×103 deg/cm, about three times as large as that along the c axis. This value is a little smaller if compared with the Faraday rotation of the orthoferrite along the a axis. The Faraday rotation of Fe3BO6 is anisotropic as in the case of orthoferrites, and is of the same magnitude as that of Y3Fe5O12, though the spontaneous magnetization of Fe3BO6 is two orders of magnitude smaller than that of Y3Fe5O12. This may be ascribed to the anisotropic character of the Fe3+ ions.