4 terminal impedance

[Noles Guy]

Hello all,

This is Noles Guy from FSU. I am doing IS on conductive material on polymer thin film using 4 linearly probes with Solartron SI 1260.

The configuration I have from Solartron :  Input and Gen output are connected to Current and V1 Low, Hi are connected to Voltage. Please tell me if this configuration is correct ?

The problem is the inconsistent results

. The pattern of  Nyquist plots are changed with:

• -the change of cables - Figure 1. My question is why there is the different in Im vs Real plot, but it seems to be indentical in Magnitude vs. Freq ??
  
• -the orientation of sample (rotate homogeneous sample on the stage results in different outcomes ) - Figure 2
• Some times Nyquist shows C, R behavior (with negative Im), other times there is inductive behavior, they seems to be symmetrical (which is suspected as the result of cables change,  but not really sure because I can not replicate) . How can it happen

I couldnt attach the file. please click on the link http://imgur.com/a/ry3vL

I appreciate any suggestions. Thank you very much

-Noles