Thanks! That's great information. We had to make our own, but it's good to see that there are decent off the shelf systems. I agree that contact resistance on t

Thanks! That's great information. We had to make our own, but it's good to see that there are decent off the shelf systems. I agree that contact resistance on these tiny samples has got to be a huge issue (can they use mercury?). However, what I've seen suggests that even the low frequency AC measurements are more complex due to capacitive coupling effects. However, narrow bandwidth lock=in should improve noise... the equipment still just claims 10u Ohm.