Hall Effect Wiring

[JB441616]

I have the

7001 switch with Hall effect Card 7065
2182A nano voltmeter
6220 current source
6485 --.

The RS 232 and trigger link are both connected in between the volt meter and the current source.

I'm Attaching a - of how i wired it. I have the 2660 output to the 7065 imput, the 7065 output to the 6485 input. I'm primarily curious about where to connect the red ground cable (if it even needs to be connected).
This set up is for thin film resistivity and hall effect.

Thank you,
-Jacob

[Dale C]

Look at the video in the following link.
That will show how to make the proper connections and crosspoint closures.
http://www.keithley.com/centralized_dis ... etid=55820

[JB441616]

I watched the video, but it does not tell you the wiring for the ground cable.

also, on a different note, I've been able to get semi-repeatable results for resistivity but my Hall mobility is pretty bad. Would there be any reason why my van der Pauw voltages would differ significantly from my hall voltages just based on instrument configuration or could it be the program?

Also do you have any suggestions for shielding the sample?

thanks

[Dale C]

Grounding in not necessary. Make sue the current source LO is connected to the ammeter LO. But that is about it.
To shield the sample use a conductive test fixture and connect it to the current source LO. That should help.
What level of resisitivity are you trying to measure? If it is very high (>1G ohm) then use the guard on the 6221 and on the 7065.

[JB441616]

Thank You for all the help Dale.

[JB441616]

Just one more question,

The Hall mobility I'm trying to measure is very small ( < 50 cm^2/Vsec). Is this set up suggested when trying to measure on this scale? Or does it mostly depend on how well we can shield and reduce noise effecting the measurements.

Thank you