magmeas

Python module enabling the import and handling of VSM-data acquired on a Quantum Design PPMS measurement system. Extrinsic permanent magnet properties can be automatically calculated from M(H) hysteresis loops and exported to YAML- or CSV-files. Basic plotting and export to HDF5 files is also available. The same functionality is available for M(T) measurements, although greater care should be taken. Manual inspection of the derived properties ist always encouraged.

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Installation

Just install with pip:

pip install magmeas

Usage

Input file formatting

For conveniently importing automatically, make sure that the necessary sample properties are given in the .DAT file. The formatting is as follows:

INFO,m,SAMPLE_MASS
INFO,(a, b, c),SAMPLE_SIZE

With m being the sample mass in mg, a and b being the sample dimensions perpendicular to the magnetization axis and c being the sample dimension parallel to the magnetization axis. So far only cuboid samples are supported and the density is assumed to be m / (a * b * c)

Python

As of right now there are four distinct classes that conveniently handle specific types of measurement data:

• VSM: general for all types of VSM measurements
• MH: for all M(H) measurements, still quite unspecific
• MH_major: for major hysteresis loop measurements
• MT: for M(T) measurements

Here is what each of them do at initialisation or automatically with a method:

	VSM	MH	MH_major	MT
import measurement data from Quantum Design .DAT file	✅	✅	✅	✅
export to HDF5	✅	✅	✅	✅
plotting	❌	✅	✅	✅
calculate properties	❌	❌	✅ $H_c$, $M_r$, $BH_{max}$, $H_k$, S, $M_s$ (optional)	✅ $T_c$
export properties to csv/yml	❌	❌	✅	✅

Additionally, exporting the properties of several MT or MH_major objects together is possible with magmeas.mult_properties_to_file. Plotting of several MH_major objects together in one graph is conveniently done with magmeas.plot_mult_MH_major. Documentation is mainly available in the form of detailed docstrings. Just use help(magmeas.VSM) or similar to get more information.

Command line

Some basic functionality is also available in the form of a command line interface. Get more information with:

magmeas -h

Dependencies

• NumPy
• Pandas
• Matplotlib
• SciPy
• h5py
• mammos-entity
• mammos-analysis

Requires Python >= 3.11 due to dependencies