# Giant magnetoresistance

for giant magnetoresistance with 3 layers suppose Fe-Cu-Fe, and suppose we take room temperature (300K) and moderate layer thickness (eg Fe = 30 Amstrong, Cu = 20 Amstrong),

what is the typical magnetoresistance we get? I mean the maximum resistance (in ohms) when the magnetization of the FM layers are antiparallel (i am not asking the GMR ratio delta r/ro).

Is it in the order of few tens of ohms, hundreds of ohms, kilo ohms ?

i just want rough estimate. all references i saw talk about the gmr ratio only, not the actual resistance.

thank you.

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michaeltorrent said:
Is it in the order of few tens of ohms, hundreds of ohms, kilo ohms ?
i just want rough estimate. all references i saw talk about the gmr ratio only, not the actual resistance.
You can make a rough estimate using the bulk resistivity of copper and/or of iron. So it depends on the other dimensions of the film (length and width).

If we just take the sheet or surface resistance of a 10 Å film, one would divide the bulk resistivity by the thickness: (10^-8 Ohm.m)/(10^-9 m) = 10 Ohm (per square).

(Of course, this does not really work when dimensions become smaller than the electron mean free path. I copper at room temperature, this is about 300 Å. It only gives a rough estimate.)

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hey .. guys . ... I was wondering if any one did some exerimental work on GMR .. I have been trying to get GMR in nanowires but have not been successful .. I have tried varying pulse timing but have had no luck .... Can any one help me out??