Dilute Magnetic Semiconductor Theoretical Aspects

This exchange field in Fe is huge and much larger than the magnetic field due to ions in the crystal. A magnetic ion produces a field of Be = w 10 Gauss at the 

In dilute magnetic semiconductors doped with Mn (when the concentration of Mn issmall,thatis,x 0.01),theMn + spins can be regarded as isolated from one another in which case the magnetization can be described by using the standard Brillouin function as 

In the low field and high temperature limit (i.e., when gMnltBSH/(kT) 1), M is linear in H and static (DG) magnetic susceptibility %, defined by M = % H is of the Curie form [12] 

For DMS with sufficiently large magnetic ion concentration, where the magnetic ions can no longer be considered to be isolated, the magnetization cannot be expressed by the standard Brillouin function because of the M — Mn interactions. At low magnetic fields, M has been found to be linear in H as in the dilute case. At high temperatures and low fields, % follows a Curie-Weiss behavior described as 

For an external magnetic field B applied along the z-direction, the magnetization Mz of a DMS alloy containing Mn + ions is empirically written as 

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