how to set the initial spin for Fe/MgO/Fe MTJ

[leslie]

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

[zh]

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.

[Anders Blom]

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

[leslie]

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?

[zh]

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