Author Topic: Negative TMR  (Read 2616 times)

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Offline karn

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Negative TMR
« on: February 11, 2015, 08:12 »
Hi,

I intend to calculate TMR at diff. bias voltages for a MTJ. Now i read in one paper the TMR equation which is (Ipc-Iapc)/Iapc. Unfortunately in my case Iapc is greater than Ipc at all bias voltages (Am i wrong right here?  ::))  and hence according to the aforementioned TMR eq. i get negative TMR. So i was wondering if it was justifiable to have negative TMR or i should really tinker the equation a little like (Iapc-Ipc)/Ipc. I am waiting for a comment on this..!!

Offline Anders Blom

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Re: Negative TMR
« Reply #1 on: February 14, 2015, 13:22 »
So, it just means your AP current is larger. Depending on the electronic states, this can certainly happen. And yes, I would agree with you that the second version of the formula makes more sense in this case. In the end, the "TMR" is just a figure of merit, the real results of your calculation are Iapc and Ipc, so as long as you present those clearly, and the method used to compute the TMR, nothing is "wrong".