Questions tagged [magnetism]
For questions about magnetic systems and materials
57
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Why can't DFT calculate the energy of magnetic diatomic molecules accurately?
I am trying to calculate the reaction enthalpy change of $\ce{2H2 + O2->2H2O}$, my plan is to calculate the energy of $\ce{H2, O2 \text{and} H2O}$, respectively, then do the simple math.
But I find ...
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How to find magnetic materials in terms of magnetic point group?
Are there any methods to find materials in terms of the assigned magnetic point group? For example, I know the magnetic point groups $6'mm'$ and $6'22'$, and I want to find the corresponding ...
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Hysteresis loop and anisotropy
I was reading a manual on magnetic materials. It has discussed the origin of hysteresis of ferromagnetic materials, but it is not clear to me whether or not it depends on anisotropy. I understand that ...
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83
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How to calculate the magnetic anisotropy energy using the VASP code?
I want to calculate the magnetic anisotropy energy of the CrI$_3$ monolayer which has 8 atoms per unit cell. I have understood from VASPWIKI that there are two steps:
A standard SCF collinear ...
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67
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How to set the AFM configuration in this doped monolayer system?
The figure below illustrates a 2x2x1 supercell of transition metal-doped CrI$_3$ monolayer. The red, green, and black atoms represent Cr, I, and transition metal atoms, respectively. I want to ...
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Which one should be investigated first? dynamic stability or magnetic stability?
I would like to investigate the stability of $\ce{VI_3}$ monolayer, but I am confused about whether I start directly by performing Phonon spectrum calculation, or I should first investigate the ...
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49
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Modeling magnetic field of permanent magnet: Where to start? [closed]
I would like to model magnetic field of a permanent magnet like this one magnet . Ideally, I would like to do it python or any other language. I would like to start with some simple geometry and some ...
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What are Crystal Electric Field Parameters?
What does the following notation mean?
$$A_{20}\left<r^2\right> = -100 \mathrm{K}$$
Where $A_{20}$ is termed a Crystal Electric Field Parameter.
I often see this notation when reading papers on ...
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74
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How to change the magnetization direction in Quantum ESPRESSO?
I have a magnetic crystal system. I want to calculate the total energy of the system if the magnetization direction is aligned in different directions such as [110], [010]. By default Quantum ESPRESSO ...
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9
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How is SYMPREC used to determine symmetries compatible with local magnetic moments in VASP?
In DFT calculations using vasp, symmetry analysis are performed to determine space group symmetries at first, if symmetrization is turned on, such as ISYM = 2. When magmoms are set in INCAR, ...
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How to define ferrimagnetism in Quantum ESPRESSO
I would like to pick this problem from my previous post See link.
I am clear about how to define antiferromagnetism in QE.
Here I am with another issue.
I am ...
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How to make ferro, feri and antiferro magnetic structure for QE
I have below &SYSTME information from my input file
...
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2
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177
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Magnetic Transition Pymatgen Error
I am trying to simulate the change in magnetic moments during a ferromagnetic to antiferromagnetic transition.
...
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Why does the S squared value have no meaning in Density Functional Theory?
It is not the first time that I stumble upon the affirmation that spin and the $S^2$ value, under DFT, has no "real physical meaning". Why?
If that is true, why are we using it all the time ...
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Band unfolding for magnetic systems [closed]
I'm trying to study the electronic structure of a 1D antiferromagnetic (in which the spin is associated with copper atoms) system, via spin-polarized calculations.
The unit cell dimensions are ...
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How can I calculate the J value in an antiferromagnetic material?
I am new to DFT, especially in doing DFT for magnetic materials. I recently came across this paper which indicated the calculation of the J value in the case of antiferromagentic materials as per the ...
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136
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How to study a new material without any experimental data about it?
My question is a little bit general. I want to study a 2D monolayer material which hasn't any experimental data available, just some first principles DFT works using PBE, LDA and HSE06 (for band ...
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Handling multiple self-consistent solutions with DFT+U
It is well-established that within the DFT+U framework, one can achieve several self-consistent solutions with greatly varying energies for the same exact magnetic ordering. In 2010, Meredig et al. ...
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How can I obtain seperate spin-up and spin-down bands while considering Spin Orbit Coupling in Quantum ESPRESSO?
I have been studying a magnetic material with SoC taken into consideration. The main aim was to obtain the band structure.
when I use spin_component = 1 in the ...
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Are these settings for HSEsol accurate enough?
I have conducted HSEsol relaxation on a monolayer unit cell of 3 atoms using VASP, with the settings below :
...
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Will there be a difference between GGA and GGA+$U$ for material with Sc element involved?
I have a material that contains the transition metal element Sc [3$d$1], and I want to know your opinions if there will be a difference between GGA and GGA+$U$ calculation. Knowing that the other ...
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262
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How to perform HSEsol in VASP calculations?
I want to perform HSEsol (PBEsol + HSE06) calculation on a material (monolayer) that doesn't have experimental data available. Could you please tell me how to ...
- 5,546
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Is it possible to calculate the variation of magnetization M(T) for a diluted magnetic semiconductor? [closed]
Is there any simulation program (for example a DFT package) to determine the variation of magnetization M(T) for dilute magnetic semiconductors or doped semiconductors with different concentrations of ...
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Can we consider SOC in FM materials using QE?
This is a follow-up question to my question posted here. I've been trying to study the effects of spin-orbit coupling (SOC) on the band structure of ferromagnetic (FM) material VSe$_{2}$. The input ...
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How to determine the value of the difference (U-J) in "Dudarev's approach" for GGA+U calculation using the VASP?
I want to conduct GGA+U calculations using Duradev's approach in VASP code on a ...
- 5,546
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202
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How can I properly represent paramagnetic materials in DFT calculations?
I have seen specific ways of constructing input files for
Anti-ferromagnetic materials
Ferromagnetic materials.
How can I represent a paramagnetic material in plane wave DFT codes like Quantum ...
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367
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Are different eigensolvers consistent within VASP (Algo=Normal vs Fast)
I tried to relax a 4x4x1 supercell of ferromagnetic monolayer material using the default settings (ALGO = Normal) but it didn't converge. So, I switched to ...
- 5,546
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PT-symmetry leading to spin-degenerate band structures
I am trying to understand the fundamental physics of a kind of problem. I will introduce a specific example and then list some of the broader qualms I hold. I have observed many band structures, be it ...
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Getting different total magnetic moment in 'scf' and 'vc-relax' calculations in Quantum ESPRESSO
I am performing a spin polarized DFT calculations in Quantum Espresso on a Co2MnSi ferromagnetic crystal. For this I have performed these steps:
1) Performed ...
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18
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Ising model: How can I spot the critical point?
Consider a zero-field Ising model with $N$ spins and periodic boundary conditions, with the Hamiltonian given by:
$$H = -K \sum _{(ij)} s_i s_j\tag{1}$$
in 1D and 2D, where $K = \frac{J}{k_BT}$, where ...
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Is it possible to calculate the Curie temperature for magnetic systems?
Using DFT calculations we can know the electronic and magnetic property of the system at 0 K. I am wondering if there is any computational method to know the curie temperature of magnetic materials? ...
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Is the "Final Magnetic moment" in the materials project repository same as the "total magnetization" value in Quantum ESPRESSO output files?
I'm quite new to spin-polarized DFT and have been trying to study $BaVSe_{3}$ which is ferromagnetic (with a Final Magnetic Moment of 0.052 Bohr Mag) as per the Materials Project repository [picture 1]...
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How can I assign spins to an non-planar Anti-Ferro Magnetic system (CoO in this case)?
I have been working with an anti-ferromagnetic material Cobalt Oxide. And in the image given below the blue spheres are Co ions. The blue spheres form a tetrahedron shape.
And I've assigned the spin ...
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Are there any codes to study magnetic materials?
I have used a few codes for studying magnetic materials (specifically core-shell nanoparticles with an AFM shell and an FM core). These are:
Vampire: For the calculation of curie temperature via ...
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Orbital magnetization in periodic solids
The orbital magnetization in periodic solids has been nicely described by the so-called modern theory of magnetization [1,2,3,4].
$$\tag{1}
\mathcal{M}_{orb} = -\frac{1}{2} \Im \sum_{n,\mathbf{k}} f_{...
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How to calculate the exchange matrix of a bilayer magentic system?
I have been using the Vampire atomistic simulation software for a while and it has a useful simulation for predicting the curie temperature. But in order to do that I need the exchange matrix of Co-...
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How to visualize MuMax3 shapes?
I'm new to micromagnetics and the finite difference method. The mumax3 software lets you create a variety of geometric shapes. I would like to create a core-shell particle to study magneto-electric ...
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How to predict new Half Metallic materials with higher degree of spin polarization?
Using DFT calculations, how one can predict the new half metallic materials with higher degree of spin polarization. I want to know the steps which have to be followed in prediction of new materials. ...
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How to do spin polarization calculations using Quantum ESPRESSO?
I am currently new to DFT calculations in Quantum ESPRESSO. Though, I have read some research papers for determining spin polarization and Half-metallicity in certain Heusler alloys. These research ...
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Predicting magnetic moment of a metal complex computationally
Recently, for entrance exams, I have been dealing with a lot of weird compounds. One of them is $\ce{K3[Mn(CN)6]}$.
The objective was to predict the magnetic moment of the above complex.
I predict ...
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When should spin polarized calculations be done?
Should the presence of a d block element in the unit cell mandate the need for performing spin-polarized calculations? I wanted to find out the DOS, PDOS, and the band structure. I'm new to DFT and I'...
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How to automatically plot atomic structures with magnetic moments?
I work with magnetic materials and I haven't found a way to automatically plot structures with their corresponding magnetic moments. For this specific project I am using VASP. I am trying to plot ...
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136
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Spin density in systems with non-collinear magnetism using VASP
I have recently been working with non-collinear antiferromagnetic systems. I understand that, in order to obtain spin density, one must obtain the electron density in one configuration of spin and ...
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Magnetism and Topology
Can magnetism and topological insulating behavior coexist in a material? If yes, can someone refer to a recent work?
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What measured quantity can be associated to the value of the J parameter in the Heisenberg/Ising hamiltonians?
This question is related to other one here in the MatterModelingSE:
Is it possible to calculate/estimate the value of the J parameter to be used in the Heisenberg/Ising hamiltonians?
Here J is the ...
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Is it possible to calculate/estimate the value of the J parameter to be used in the Heisenberg/Ising Hamiltonians?
Studying magnetic systems, two frequently used approximations are the Heisenberg and Ising models (a discussion about these approximations can be read here):
\begin{equation}
\tag{Heisenberg}
\hat{H}...
- 18.5k
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How accurately are magnetic effects treated in *ab initio* methods?
I am a condensed matter theorist and I mostly use quantum Monte Carlo methods. I use models like the Heisenberg model, an represent an extreme simplification of real materials to just localized spin ...
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How is the material $\ce{\alpha-NaMnO2}$ pronounced?
I am a theoretical physicist, so I am not very familiar with chemical names. The material I am interested in is $\ce{\alpha-NaMnO2}$. Would that be pronounced alpha sodium manganese dioxide? Is it ...
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Is Heisenberg model or in its simplier form Ising model a good approximation to study magnetic systems?
Heisenberg model
$$\hat{H}=-\sum_{\langle i j\rangle}J\hat{S}_i\hat{S}_j$$
And in its simplified version, the Ising model
$$\hat{H}=-\sum_{\langle ij\rangle}J\hat{S}_i^z\hat{S}_j^z$$
are widely ...
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What are examples of materials that closely correspond to the Heisenberg model?
I use the antiferromagnetic Heisenberg model all the time:
$ H = J \sum \limits_{\langle i,j \rangle} \vec S_i \cdot \vec S_j$
What are some examples of materials that are well-described by this ...
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