Pulsed-field measurements of the Faraday rotation (FR) spectra over a wide photon energy range for (x = 0.015) were made up to 150 T at low temperatures by means of a streak spectrometer. We observed a reversal of the direction of the FR with increasing field. Dividing the Verdet constant into a paramagnetic term in the low-field range and a diamagnetic term in the high-field part, we found that the latter exhibits anomalies at around 2.4 eV.