What Caused the Lower Resistance in the Second Graph?

[MementoMori96]

Hi, in laboratory i had a sample of Ge with p-doping. In a first place i have done different measure V vs I (first image)

Then i insert the sample in a magnetic field perpendicular to the sample.

And i have done measure of V vs B (with a fixed current at 8 mA) and i obtained the second image.

As you can see at B = 0 the R is lower than the resistance of the first graph. Why ?

I suppose this third image

The is an accumolation of positive charges at right and so we measure a lower Voltage with a lower resistance

Can be this correct?

 

[berkeman]

As you can see at B = 0 the R is lower than the resistance of the first graph. Why ?

It looks like the top of your error bar at B=0 is close to what you measured in the first test. Why are the error bars so large?

Also, temperature will affect the "resistance" reading. How did you control for temperature?

 

[MementoMori96]

Yes is close but with a Z test alpha 5% the two values are not compatible. The error bars are large due to the instruments. The temperature is the same.

What do you think about my idea?