Double Exchange in Mixed-Valency Diluted Magnetic Semiconductors |
| J. Blinowski Institute of Theoretical Physics, Warsaw University, Hoża 69, 00-681 Warszawa, Poland and P. Kacman Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa, Poland |
| Full Text PDF |
| The role of double-exchange, a non-Heisenberg spin-spin interaction between the magnetic ions of identical chemical nature but different charge states, in the mixed-valency diluted magnetic semiconductors is discussed. The mechanism correlates the spins of magnetic ions by virtual hopping of a d-electron from one ion to the other via the p-band states. We calculate the energy spectrum for pairs of magnetic ions within the charged ionic clusters stabilized by the charge-charge correlations, taking into account simultaneously both the double and the superexchange. The ferromagnetic, non-Heisenberg double exchange might compete with the Heisenberg-like, ferrimagnetic superexchange, thus resulting in canted alignments of ionic spins. |
| DOI: 10.12693/APhysPolA.90.731 PACS numbers: 71.70.Gm, 75.30.Et |