Strain broadening of the magnetization steps in diluted magnetic semiconductors

We show that the bond-length mismatch in magnetic solid alloys (diluted magnetic semiconductors) results in fluctuations of the exchange constants between neighboring magnetic ions. We present the theory of these fluctuations and analyze their effect on the broadening of magnetization steps observed in these materials. We conclude that the effect is quantitatively comparable to the effect of the Dzyaloshinski-Moriya interaction, but produces a different behavior of the magnetization curve, which gives a possibility to distinguish between these mechanisms experimentally.