Magnetotransmission measurement of ferromagnetism origin in Mn-doped ZnO films

Magnetotransmission spectroscopy, the optical absorption measurement using circularly polarized light in the range from far infrared to near ultraviolet, is a direct method to study the energy structure of diluted magnetic semiconductors. In this paper, the magnetotransmission measurement is performed on the ferromagnetic Mn-doped ZnO films. The splitting between two circularly polarized light absorption edges is up to 10 meV under external magnetic field of 0.8 T at room temperature. The splitting is closely follows the magnetization of the films, as measured using Vibrating Sample Magnetometer. The observed ferromagnetic-type splitting of absorption edge is explained by antiferromagnetic p-d exchange interaction.