QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Om Prakash Upadhyay on November 11, 2016, 06:22

Title: Magnetism
Post by: Om Prakash Upadhyay on November 11, 2016, 06:22

Hello.......
how ca we examine ferromagnetic and ferrimagnetic material  from ATK-DFT.
Reply plez...........

Title: Re: Magnetism
Post by: zh on November 11, 2016, 11:58

Look at the specification of 'InitialSpin':
http://docs.quantumwise.com/manuals/Types/InitialSpin/InitialSpin.html

Title: Re: Magnetism
Post by: Om Prakash Upadhyay on November 11, 2016, 13:21

please, clearyfy me that haw can we identify ferromagnetic or ferrimagnetic behaviour?????
The .py file is attached as below

Title: Re: Magnetism
Post by: zh on November 12, 2016, 03:24

If the initial spins of all copper atoms are specified with a same non-zero value, the calculations may converge the ferromagnetic states.
If the initial spins of some of copper atoms are specified with a same non-zero value (e.g., x), while the initial spins of the remaining copper atoms are specified with a value smaller than x,  the calculations may converge to the ferrimagnetic states. 

In the actual situation, the ferrimagnetic state may not exist or it may be in a very high state,  the calculations will difficultly  or even can't converge to the real ferrimagnetic state.

Title: Re: Magnetism
Post by: Om Prakash Upadhyay on November 12, 2016, 06:52

Thanks a lot for reply.
    According your reply 'zh',either we have to see iitial state of copper on mulliken population or any other else?
I have attached mullike population file as below.
please help me how can I idetify either it is ferromagnetic or ferrimagetic?

Title: Re: Magnetism
Post by: zh on November 12, 2016, 12:07

After the self-consistent calculation is finished, you can check the magnetic moment of each atom by the mullliken charge population (the spin-up charge   -  the spin-down charge), just as you said.

Title: Re: Magnetism
Post by: Om Prakash Upadhyay on November 12, 2016, 12:26

Thanks a lot for reply..............
Yes I did and found different value of magnetic moment (some are same) of each atom by the mulliken charge population (the spin-up charge - the spin-down charge). The total magnetic moment is about 6µ. What does it mean?  either it is ferromagnetic or ferrimagnetic?
What is the main clue behind it to understand? Please clearify the result.........

Title: Re: Magnetism
Post by: Anders Blom on November 12, 2016, 14:08

I would suggest that you first learn the basic theory of ferro- and ferrimagnetism from some websites or books, else you will not be successful anyway. Your opening statement is that you want to study these properties, but unless you know what they are, running a calculation will not help you understand the concepts or get any sensible results.