Zeeman splitting in ferromagnetic Schottky barrier contacts based on doped EuS

Abstract

Schottky barrier contacts of nonstoichiometric EuS, a ferromagnetic semiconductor, have been fabricated on Si (100) substrate and the current–voltage (I–V) characteristics are investigated at temperatures 150–5.0K. The electrical transport across such Schottky contacts is found to be dominated by thermionic emission at high temperatures, while at low temperatures and low biases, electron tunneling is dominant. The lower bound estimate of the Schottky barrier heights was obtained by analyzing the high-bias current–voltage characteristics. A decrease in barrier height of 0.26±0.06eV was deduced from the I–V characteristics as the temperature decreases below the ferromagnetic ordering temperature (TC) of the EuS. The variation of the barrier height below TC is the result of a spontaneous Zeeman splitting of the conduction band, and its temperature dependence resembles that of the spontaneous moment in EuS. The results point to the plausibility of using doped EuS as a spin injector and detector.