Dear Asa, it is difficult to guess without knowing the details, but here are some condensed remarks concerning magnetism in Siesta:
1. If you set SpinPolarized flag True (as you should) and do nothing else, the initial spin values will be set to maximum on all atoms. This might be OK for your Fe-Co system. But if you have other atoms which are not a priori magnetic, or you want to model e.g. antiferrimagnetic configuration you should influence initial settings of spins using the DM.InitSpin block. 2. In order to figure out what the local moments are you should set WriteMullikenPop 1 and you'll see spin up/down charges on every atom. 3. If the magnetic solution is not what you expect it is important to understand how it came about in the course of self-consistency - do the magnetic moments gradually disappear? Were they small and go gradually evolve in the right sense? Are some of them inverted with respect to what you expected? For this, stop calculations after certain number of iterations and run an extra calculation with WriteMullikenPop 1 again. 4. If the magnetism gradually disappears where it shouldn't, a too high ElectronicTemperature may be responsible. Of, of course, an error in structure (e.g., too cloose atoms). Best regards Andrei Postnikov > Dear siesta users.. > I am new user of siesta. > I am doing calculations of an Fe/Co nanowire. My system contains 18 > atoms. > As both Fe and Co are magnetic, I have set the spin polarised flag true. > In > the output it is shown that > Total spin polarization (Qup-Qdown) = 5.471783 > I understand that this value is in bohr magneton and it is the total > magnetization of the nanowire. But this value is very low as the > individual > magnetic moments of Fe and Co are around 2.2 and 1.7 respectvely. > Previously I have done calculations of the same system in VASP and the > total > magneticmoment of the system is 36 bohr magneton.. > Can anybody please explain what is wrong / what is the way to get the > local > and total magnetic moment frm the siesta output file..I am doing a > collinear > calculation.. > thanks in advance > Asa >
