pymatgen.command_line.vampire_caller module

This module implements an interface to the VAMPIRE code for atomistic simulations of magnetic materials.

This module depends on a compiled vampire executable available in the path. Please download at https://vampire.york.ac.uk/download/ and follow the instructions to compile the executable.

If you use this module, please cite the following:

“Atomistic spin model simulations of magnetic nanomaterials.” R. F. L. Evans, W. J. Fan, P. Chureemart, T. A. Ostler, M. O. A. Ellis and R. W. Chantrell. J. Phys.: Condens. Matter 26, 103202 (2014)

class VampireCaller(ordered_structures=None, energies=None, mc_box_size=4.0, equil_timesteps=2000, mc_timesteps=4000, save_inputs=False, hm=None, avg=True, user_input_settings=None)[source]

Bases: object

Run Vampire on a material with magnetic ordering and exchange parameter information to compute the critical temperature with classical Monte Carlo.

user_input_settings is a dictionary that can contain: * start_t (int): Start MC sim at this temp, defaults to 0 K. * end_t (int): End MC sim at this temp, defaults to 1500 K. * temp_increment (int): Temp step size, defaults to 25 K.

Parameters:

  • ordered_structures (list) – Structure objects with magmoms.

  • energies (list) – Energies of each relaxed magnetic structure.

  • mc_box_size (float) – x=y=z dimensions (nm) of MC simulation box

  • equil_timesteps (int) – number of MC steps for equilibrating

  • mc_timesteps (int) – number of MC steps for averaging

  • save_inputs (bool) – if True, save scratch dir of vampire input files

  • hm (HeisenbergModel) – object already fit to low energy magnetic orderings.

  • avg (bool) – If True, simply use <J> exchange parameter estimate. If False, attempt to use NN, NNN, etc. interactions.

  • user_input_settings (dict) – optional commands for VAMPIRE Monte Carlo

  • sgraph (StructureGraph) – Ground state graph.

  • unique_site_ids (dict) – Maps each site to its unique identifier

  • nn_interactions (dict) – {i: j} pairs of NN interactions between unique sites.

  • ex_params (dict) – Exchange parameter values (meV/atom)

  • mft_t (float) – Mean field theory estimate of critical T

  • mat_name (str) – Formula unit label for input files

  • mat_id_dict (dict) – Maps sites to material id # for vampire indexing.

static parse_stdout(vamp_stdout, nmats)[source]

Parse stdout from Vampire.

Parameters:

  • vamp_stdout (txt file) – Vampire ‘output’ file.

  • nmats (int) – Num of materials in Vampire sim.

Returns:

MSONable vampire output. critical_temp (float): Calculated critical temp.

Return type:

parsed_out (DataFrame)

class VampireOutput(parsed_out=None, nmats=None, critical_temp=None)[source]

Bases: MSONable

This class processes results from a Vampire Monte Carlo simulation and returns the critical temperature.

Parameters:

  • parsed_out (json) – json rep of parsed stdout DataFrame.

  • nmats (int) – Number of distinct materials (1 for each specie and up/down spin).

  • critical_temp (float) – Monte Carlo Tc result.