Tektronix Technical Forums are maintained by community involvement. Feel free to post questions or respond to questions by other members. Should you require a time-sensitive answer, please contact your local Tektronix support center here.

Resistance measurement artifact during sudden change in resistance

Post Reply
bua123
Posts: 2
Joined: February 17th, 2020, 11:09 pm
Country: India

Resistance measurement artifact during sudden change in resistance

Post by bua123 » February 19th, 2020, 3:56 am

Hi,
I am having trouble with the measurement of resistivity. I am doing a temperature-dependent resistance measurement. Basically I am acquiring voltage and current data with the temperature sweep of 100 K to 360 K range. I am using keithley 2450 SMU. I configured it for 4 wire sensing mode, where the source is constant current and measuring the voltage across the sample. My material undergoes metal to insulator transition depending on temperature. So, when it transforming the resistance (metal to insulator or vice versa) suddenly with temperature, there is an artifact of the measured voltage close to the transition temperature for both during cooling and heating. I looked clearly, the current source value is proper but the measured voltage value is not. I am attaching a few figures to make it clear. Please if anybody has any suggestions on it help me. Thanking you.
Attachments
T_vs_R.PNG
T_vs_R.PNG (11.25 KiB) Viewed 524 times
T_vs_R_zoomed.PNG
T_vs_R_zoomed.PNG (14.73 KiB) Viewed 524 times
T_vs_Voltage_and_current.PNG
T_vs_Voltage_and_current.PNG (18.84 KiB) Viewed 524 times

bua123
Posts: 2
Joined: February 17th, 2020, 11:09 pm
Country: India

Re: Resistance measurement artifact during sudden change in resistance

Post by bua123 » February 23rd, 2020, 9:07 pm

Hi all,
I am could not fix the problems yet. I am waiting for a suggestion. If anyone has an idea for fixing this above problem, please inform.
Thanks

Andrea C
Keithley Applications
Keithley Applications
Posts: 1490
Joined: October 15th, 2010, 10:35 am
Country: United States
Contact:

Re: Resistance measurement artifact during sudden change in resistance

Post by Andrea C » February 28th, 2020, 4:12 am

To be honest, it’s not clear to me what the graph should look like. The material has hysteresis evidently. Can you give a mock up of what you are expecting?
From the third graph, you gave us the current and the voltage vs the temperature.
At low temp, there is almost 1 volt; at high temp about 1mV.

The 10uA of sourced current does not seem as flat as I’d expect. Was the instrument warmed up before the experiment was performed?
There is one current value at about 250K that dramatically changes. The graph scale does not tell us how much any of this change really is.
Are you using 10uA range?

For the source current, you specify a voltage compliance limit. How big is that? Needs to be larger, by at least 10%, than the max voltage you expect.

What about ranging? Auto ranging the voltage measure? Try fixed range (2v) to see if that gives you a more expected result.

Post Reply

Return to “Resistivity Measurements”

Who is online

Users browsing this forum: No registered users and 0 guests