Hall Effect Probe/Sample Mount (Design)

[Yondaime5685]

Me and a friend are working on a research project that involves four-point electrical measurements. (Van der pauw) To do a hall effect measurement, the sample and probes have to have a strong magnetic field pass through. So we want some design ideas on constructing the mount that will have to be suspended in a magnetic field and cause minimal interference. (Maybe some schematic pics would help or design concepts.)

The samples we will be using are thin films. (Less than a cm^2)

[Bob S]

What magnetic field range do you need to measure? Bipolar or unipolar? Do you have preference on package (e.g., flying leads vs. DIP)?

[Yondaime5685]

I'm sorry I should have said Hall voltage measurement. We will know the value of the B-field and will be solving for the sheet carrier density. Our magnet range is around .5-1.5 Tesla. Most of our work will probably be around .5-1 Tesla.
The outline we are following is here: http://www.eeel.nist.gov/812/effe.htm We will measure the Hall voltage and then change the direction of the B-field and measure again so bipolar I guess. We are using flying leads for our resistivity measurements so that would be preferred.

Here is the setup NIST is using:
http://www.eeel.nist.gov/812/images/hlleffct.jpg
We are trying to construct a similar setup.

[Bob S]

The Hall signal amplifier I believe you need is two voltage followers to give very high input impedance followed by a balanced amplifier, shown here (see attachment) with a gain of 10. R1 and R2 should always be equal, and R3 and R4 should also be equal. R3 and R4 can be increased or decreased to change gain.