Spectroscopic Detection of Magneto-Optical Hysteresis in a Single Magnetic Field Sweep by Faraday Cell Modulation

A rapid magneto-optical (MO) spectrometer is introduced. In conventional MO measurements, a monochromator produces quasimonochromatic incident light. The MO spectrum is then found by measuring the hysteresis loop at each wavelength in small steps, which is time consuming. In contrast, the new system uses 1) incident white light, 2) polarization rotation by a Faraday cell and spectroscopic detection using an area sensor, and 3) subtraction of spectra for small changes of polarization. By this method, an MO spectrum can be measured in only a few minutes with a single sweep of the magnetic field, enabling rapid exploration of the magnetic properties of a wide variety of materials.