Dear Sandeep
Ceramics are generally highly resistive samples.Hence, you can safely use two terminal measurements using a variable voltage power supply and high input impedance electrometer to measure current in pA .You can not do these measurements in air. You have to mount your pellet in a metallic sample holder and create high vacuum for electromagnetic shielding and to avoid moisture effect. You must anneal your pellet in the same sample holder for a few hours at higher temperature before taking I - V measurements so that moisture, if any, comes out from the pellets. Your pellets should be highly densed to minimize porosity. Use hot pressing technique to make pellets. I have done conductivity measurements on AlN ceramics. You can go through my research gate profile to get references.
Dear Sandeep,
The precautions described by Dr Kumar are very thorough, but may not be absolutely necessary depending on your material and what type of I-V measurement you are trying to obtain. It would help if you can clarify what type of material you are studying (composition, insulator, semiconductor, dielectric or ferroelectric etc.) and what are the measurement conditions (electric field levels, static or dynamic measurement, frequency). For static (DC) measurements on a very resistive material, you might need to use a 3-terminal (guarded) electrode arrangement. The Keithley low level measurements handbook, which is available free of charge, is a good practical guide.
http://www.keithley.co.uk/knowledgecenter
As suggested by Dr. David Hall,
Fully agree with the 3-terminal sample holder usage.
with good BNC connectors.
Make a thin ceramic sample, so that you can apply high voltages, and achieve high fields across your sample. In case you studying field dependent conduction processes.
Measure the current using a electrometer/pico ammeter, and stable DC power supply.
We prefer to use batteries (connected in series), to build up the DC voltage, and especially to ensure a pure DC voltage, (battery is a good option).
Please ensure that you don't apply too high a voltage to cause breakdown of your insulating sample.
Dear Sandeep
The procedure for the I-V measurement depends upon the type of ceramic materials (Dielectric, ferroelectric or conducting ceramics) and the responses are also different. For different ceramics you will find different I-V characteristics as well as current range (pA, μA or mA). For the ferroelectric ceramics when the applied voltage crosses threshold voltage current suddenly increases due to the switching of domains. So you need to clarify about your ceramics. For electrical measurements ceramic surfaces should be coated with good quality conducting paste. Try to get the thickness of ceramics sample as thin as possible. You can put the sample in silicone oil to avoid any electrical discharge. As suggested by others researchers use a 3-terminal sample holder.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Inorganic Materials
- Ceramics