Photo-Induced Magneto-Optical Kerr Effect in Europium Sulfide EuS

The influence of light exposure on the magneto-optical Kerr effect in the ferromagnetic semiconductor europium sulfide EuS has been studied. It has been experimentally established that when a sample is exposed to the light with a photon energy greater than the band gap, photoinduced magnetization occurs, which is associated with the formation of magnetic polarons with a large magnetic moment of about 3000 μ B . The polarons are excited in a narrow temperature range of 12–18 K and form a superparamagnetic ensemble with an average polaron lifetime of 13 μs. A method for observing photo-induced magnetization using optical pump-probe technique has been described.