Giant magneto-optical Faraday effect in GaP epilayers containing MnP magnetic nanoclusters

We report a giant magneto-optical (MO) effect in a GaP(011) epilayer with embedded MnP nanoclusters (GaP:MnP) grown on a GaP(011) substrate using metal-organic vapor phase epitaxy. The MO effect exhibits a hysteretic behavior when sweeping the applied magnetic field, thereby indicating a clear dependence upon the magnetization of the sample. The measured Faraday rotation per unit length is 60 times higher in the epilayer than that of GaP at room temperature. The role of the magnetization in the MO effect makes it possible to increase this factor even further by lowering the temperature well below the Curie point (TC) of 292 K for those samples. We observed an increase of the Faraday rotation at longer wavelengths, indicating that those GaP:MnP epilayers could potentially be useful for enhanced MO effects in the visible and infrared regions of the electromagnetic spectrum.