What is the typical resistance for GMR in 3-layer Fe-Cu-Fe configuration?

In summary, the typical magnetoresistance for giant magnetoresistance with 3 layers (Fe-Cu-Fe) at room temperature and moderate layer thickness (Fe = 30 Amstrong, Cu = 20 Amstrong) is in the order of few tens of ohms, hundreds of ohms, or kilo ohms. This can be estimated using the bulk resistivity of copper and/or iron. However, for smaller dimensions, this method may not be accurate due to the electron mean free path. If you are having trouble obtaining GMR in nanowires, you may need to experiment with different pulse timings.
  • #1
michaeltorrent
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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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  • #2
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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  • #3
hey .. guys . ... I was wondering if anyone 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 anyone help me out??
 

1. What is giant magnetoresistance?

Giant magnetoresistance (GMR) is a phenomenon observed in certain materials where their electrical resistance changes significantly in the presence of a magnetic field. This effect was first discovered in 1988 by Albert Fert and Peter Grünberg, and has since been widely studied and utilized in various technologies such as magnetic sensors, hard disk drives, and magnetic random access memory (MRAM).

2. How does giant magnetoresistance work?

GMR occurs due to the spin-dependent scattering of electrons at the interface between two layers of ferromagnetic material. In the absence of a magnetic field, electrons with parallel spins have a lower resistance compared to those with anti-parallel spins due to their different scattering probabilities. When a magnetic field is applied, the spins align and the resistance of the material changes accordingly.

3. What are the applications of giant magnetoresistance?

GMR has a wide range of applications in various fields. It is commonly used in magnetic sensors for detecting and measuring magnetic fields, such as in compasses and magnetic read heads in hard disk drives. GMR is also utilized in MRAM, a type of non-volatile memory that stores data using magnetic fields instead of electrical charges. Other potential applications include spintronics, where the spin of electrons is used to manipulate and store information.

4. What are the advantages of giant magnetoresistance?

Compared to other types of magnetoresistance, GMR offers higher sensitivity, faster response times, and a larger range of magnetic field detection. It also has low power consumption and can be easily integrated into electronic devices, making it a versatile and efficient technology.

5. Are there any challenges or limitations with giant magnetoresistance?

One limitation of GMR is that it is only effective at room temperature and below. At higher temperatures, thermal fluctuations can disrupt the alignment of electron spins and reduce the GMR effect. Additionally, the cost of producing GMR materials can be high, making it less accessible for certain applications.

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