I am measuring the mobility of organic single crystal semiconductor by using Hall effect technique. But at every time there is a drastic change in mobility values for the same crystal.
The crystal resistance is very high nearly 12 ohm. the crystal shape is well suitable for setup specifications. silver paste is used as a ohmic contact. the mobility valve shows 1cm/vs after few seconds 50cm/vs there is no change in the current and magnetic field. the current also few na=ano amp only
Hall mobility is a good parameter to describe the quality of your material.
I think ambient conditions are affecting your measurements. I will suggest you to do measurements at regular intervals of time with the same sample to verify this. Also, the mobility of organic semiconductors is around 1-10. 50 seems to be a high value to me.
i agree your suggestion, in some times i got mobility of 1Cm/VS and some times 2 Cm/Vs... and its vary some times higher ... thats why i confused... can i choose the value which is related to earlier reports.