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QuantumATK => General Questions and Answers => Topic started by: leslie on June 1, 2011, 08:50

Title: how to set the initial spin for Fe/MgO/Fe MTJ
Post by: leslie on June 1, 2011, 08:50

Dear all,

Recently I am trying to follow the tutorial Fe/MgO/Fe MTJ to learn how to calculate transport properties for such structures while encontering one question:

Why the initial spin of Fe atoms at the same electrode is set to the same direction? Shouldn't there exist both spin-up and spin-down ions within iron electrode?

leslie

Title: Re: how to set the initial spin for Fe/MgO/Fe MTJ
Post by: zh on June 1, 2011, 09:07

In this case, the bcc Fe is used as the electrode. The ground state of bcc Fe is ferromagnetic state. So the initial magnetic moments of Fe atoms in an electrode are set as a same value.

Title: Re: how to set the initial spin for Fe/MgO/Fe MTJ
Post by: Anders Blom on June 1, 2011, 09:18

One doesn't actually set the initial spin, but rather the initial spin polarization, i.e. the difference in spin up vs. down populations (normalized in a special way). More details here: http://quantumwise.com/documents/manuals/latest/ReferenceManual/index.html/ref.initialspin.html

Title: Re: how to set the initial spin for Fe/MgO/Fe MTJ
Post by: leslie on June 2, 2011, 02:47

Thanks, the tutorial is really beneficial to me. However, it only illustrates single iron as electrode: first conduct a bulk calculation to get a good guess for the initial spin. How about the case for alloys, say Co2MnSi as electrode. Should we carry on bulk calculation for Co, Mn, Si seperately, or Co2MnSi as a whole?

Title: Re: how to set the initial spin for Fe/MgO/Fe MTJ
Post by: zh on June 2, 2011, 03:41

Only the bulk Co2MnSi compound should be carried out for checking the magnetic properties.