Carrier induced ferromagnetism in Mn-doped ZnO: Monte Carlo simulations

Abstract

Ferromagnetism in Mn-doped ZnO is investigated by Monte Carlo simulations assuming indirect exchange interaction via two different competing mechanisms: (i) antiferromagnetic superexchange and (ii) an oscillating carrier mediated interaction. The calculations are performed for p - and n -type samples. The Mn ion is taken as a substitutional impurity and its concentrations varied from 3% to 20%. The carrier concentrations (holes or electrons) were tested in the range of 1× 1016 -1× 1020 cm-3. These simulations showed paramagnetic, ferromagnetic, and spin-glass behaviors for the p -type samples depending on the Mn and hole concentrations. On the other hand, no phase transition was observed for the n -type samples, whatever the Mn and electron concentrations used in the simulations. © 2008 American Institute of Physics.