https://github.com/tgwoodcock/convmag
Conversion between units used in magnetism
https://github.com/tgwoodcock/convmag
conversion magnetic magnetism python units
Last synced: 5 months ago
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Conversion between units used in magnetism
- Host: GitHub
- URL: https://github.com/tgwoodcock/convmag
- Owner: tgwoodcock
- License: mit
- Created: 2021-07-03T18:52:54.000Z (almost 5 years ago)
- Default Branch: main
- Last Pushed: 2025-04-10T11:42:16.000Z (about 1 year ago)
- Last Synced: 2026-01-06T17:58:48.117Z (5 months ago)
- Topics: conversion, magnetic, magnetism, python, units
- Language: Python
- Homepage:
- Size: 47.9 KB
- Stars: 5
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
[](https://pypi.python.org/pypi/convmag/)
[](https://pypi.python.org/pypi/convmag/)
# convmag
Conversion between various units used in magnetism
The conversions between *base units* available are:
T <-> G : 1e4
T <-> Oe : 1e4
A/m <-> T : MU_0
A/m <-> G : 1e4 * MU_0
G <-> Oe : 1
A/m <-> Oe : 1e4 * MU_0
emu/cm^3 <-> T : 1e3 * MU_0
erg/Oecm^3 <-> A/m : 1e3
emu/g <-> Am^2/kg : 1
J/m^3 <-> GOe : 1e8 * MU_0
J/m^3 <-> erg/cm^3 : 1e1
erg/cm^3 <-> GOe : 1e7 * MU_0
Am^2 <-> emu : 1e3
Am^2 <-> erg/G : 1e3
Am^2 <-> erg/Oe : 1e3
emu <-> erg/G : 1
muB <-> Am^2 : MU_B
muB <-> emu : 1e3 * MU_B
muB/fu <-> T : requires user input of lattice parameters
(the factors given above are for the forward conversion)
- permeability of free space, MU_0 = 4 * 3.14159 * 1e-7 H/m (== Vs/Am)
- Bohr magneton, MU_B = 9.274015e-24 Am^2
(muB is the unit string for conversions with Bohr magnetons)
The *prefactors* available for any base unit are: M (1e6), k (1e3), m (1e-3), µ (1e-6)
You can combine *prefactors* and *base units* to give e.g. MA/m or kJ/m^3
### A word about emu
emu is not a unit but indicates the system of cgs units being used (emu == electromagnetic units)
The magnetisation data from magnetometers is very often given in emu, and in these cases emu implies the units erg/G.
This is why the equivalence emu = erg/G is given above. Many authors still quote emu/g or emu/cm^3 and therefore,
these conversions are listed in the table above. convmag always assumes that emu has the units erg/G.
**In some cases emu may take other units, so it's always worth checking this!**
## Installation:
### Pip
You can install the current release with pip:
```bash
pip install convmag
```
Pure python, no other dependencies.
Requires Python >= 3.6 because f-strings are used
## Usage options:
1) command line: a console script is provided and should be located in the Scripts directory of
your Python distribution after installation. If you have this directory in
your Path (environment variable on Windows) you can start the program by
typing "convmag" in the terminal. In this case only single values can be
converted (one at a time).
2) the package can be imported into python and then you can pass numpy arrays
into the function convert_unit(), making sure to keep the default verbose=False.
That way many values can be converted at once. The converted
values are returned as a numpy array for further processing.
```python
>>> import numpy as np
>>> import convmag as cm
>>> vals_in_T = np.arange(0, 100, 20)
>>> vals_in_T
array([ 0, 20, 40, 60, 80])
>>> vals_in_Oe = cm.convert_unit(vals_in_T, "T", "Oe", verbose=False)
>>> vals_in_Oe
array([ 0., 200000., 400000., 600000., 800000.])
```
## Converting between Bohr Magnetons per formula unit and Tesla
This conversion requires additional user input of:
- the lattice parameters *a*, *b*, *c* and *gamma*, and
- the number of formula units per unit cell.
Only orthogonal (cubic, tetragonal and orthorhombic) and hexagonal unit cells can be handled
and therefore *gamma* = 90° or 120°.
As an example of the number of formula units per unit cell, Nd2Fe14B is the formula unit, which
has 17 atoms, and the unit cell contains 68 atoms, so in this case there are 4 formula units per unit cell.
After calling "convmag" in the command line, the conversion from muB to T looks like this:
```
Input: 2.3 muB/fu T
***INFO: muB per formula unit <-> T***
Please enter lattice parameters: a b c in Angstrom
a b c: 3.0 3.0 4.0
Limited to orthogonal or hexagonal unit cells:
Please enter gamma in deg. (90 or 120): 90
Please enter the number of formula units per unit cell:
f.u./unit cell: 2
2.3 muB per f.u. = 1.48913 T (2 f.u./unit cell, cell volume = 3.600e-29 m^3)
```
## Code Archive and Citation
This code is archived on Zenodo and can be cited using the following doi and
associated metadata: [](https://doi.org/10.5281/zenodo.15182513)