Release Notes#

Version 2.0.0#

2025-02-01

This is a major release. For a comprehensive explanation of all changes, see TetraX.2: Cleaner, more convenient and reliable.

Major changes#

  • The Sample class has been completely restructured to be much simpler. Samples are now configured through composition and can have a GeometryType and MagneticOrder attribute. The old create_sample() factory has been removed. Instead, samples are now created simply by creating an instance of the Sample class.

  • The mesh and sample geometry is now managed by the SampleMesh class. The mesh of a sample can be addressed as sample.mesh. Similarly, one now has to do sample.mesh.nx.

  • Material parameters are now handeled by the SampleMaterial and MaterialParameter classes. The material of a sample is addressed as its sample.material attribute. Instead of sample.Msat, one should now use sample.material["Msat"], etc. Almost all material parameters can now be inhomogeneous. For details, see TetraX.2: Cleaner, more convenient and reliable.

  • The way experiments are being run has been changed completely. There is no more ExperimentalSetup object. Instead, major experiments act as functions on the sample and generate a Result as an output. Depending on the particular experiment, each Result provides methods to plot the calculated data and perform post-processing on it. For example, the EigenResult allows calculating the power absorption of the a spin-wave spectrum with respect to a specified microwave antenna using the EigenResult.absorption() method (which returns an AbsorptionResult).

  • By default, each Result is automatically saved to the disk. This includes the calculated data itself, as well as some metadata and the parameters used to perform the calculations. It also comes with a report.json file that contains material parameters, experiment configuration, metada (such as the version of TetraX that has been used) and can be used, for example, for data archiving. By default, running the same experiment twice will overwrite the old results.

  • Experiments can now be labeled to avoid overwriting existing data.

  • Magnetic interactions are now modularized as Interaction s in the tetrax.interactions module. The different interactions of a sample are now listed in its interactions attribute. Each interaction has an InteractionName that allows to address it. For more details, see TetraX.2: Cleaner, more convenient and reliable.

New features#

  • Integrated plotting for results of TetraX experiments.

  • New experiment relax() for more reliable equilibration based on integration of the overdamped LLG.

  • New WAVEGUIDE_AXIAL. This geometry type combines axial with translational symmetries and allow to efficiently model round wires, tubes, or multitubes by only modeling the magnetic system within a one-dimensional mesh along the radial direction. The spin-wave modes are directly calculated as function of wave vector \(k\) and azimuthal mode index \(m\) in the angular direction.

  • A new microwave antenna (MultiStriplineAntenna) has been added, which allows to model an arbitrary series of stripline antennae (e.g. to model a meandering antenna).

  • The symmetry breaking direction material["e_d"] of the InterfacialDMI can now be chosen freely.

  • Both InterfacialDMI and BulkDMI now satisfy proper boundary conditions at the sample boundary. Open boundary conditions can be recovered by setting the open_boundary attribute of the respective interaction to True, which requires to call the update_matrices() function of the interaction. Setting open boundary conditions should be done with care (that’s why this feature is kind of hidden).

  • A couple of template materials have been added, which are available in the new tetrax.materials module. They can be listed by accessing tetrax.materials.available.

Examples#

Minor Changes#

  • Samples cannot be created anymore without specifying a mesh.

  • By default the magnetization of a sample will now be initalized to the \(z\) direction. Before, it was undefined.

  • The number of CPU cores num_cpus when calculating an eigen spectrum is now -1 by default (all cores are used).

  • Frequencies are now stored in Hz, wave vectors in rad/m.

  • The plot method of the sample has been removed and its functionality absorbed into the show method.

  • The library of template geometries tetrax.geometries has been restructured and subdivided into more meaningful submodules such as tetrax.geometries.waveguide or tetrax.geometries.layer. All template geometries have been cleaned up (e.g. keywords have more meaningful names) and can be listed using tetrax.geometries.available.

  • All template vectorfields have been cleaned up and can be accessed with tetrax.vectorfields.available.

  • Both vectorfields and geometries can now be read from a file using tetrax.geometries.from_file() or tetrax.vectorfields.from_file().

Other#

  • The user guide, API reference and publication list have been updated.

  • Links to the TetraX user forum have been added.

Version 1.3.3#

2023-12-20

Hotfixes#

  • fixed wrong scaling factor in iDMI tensor (We thank Joo-Von Kim for highlighting this issue)

Version 1.3.2#

2023-10-17

Hotfixes#

  • fixed problem related to mode visualization that was appearing on windows machines.

Version 1.3.1#

2023-06-12

Hotfixes#

  • fixed installation problem on Windows related to compilation

  • fixed problem related to multiprocessing on Windows

  • fixed error on calculating absorption when some frequencies are NaN (now it properly skips these modes)

Other#

  • included description in documentation on how to use TetraX in standalone python scripts.

Version 1.3.0#

2023-05-23

tl;dr#

  • inhomogeneous material parameters

  • extract data along curves

  • new sample visualization

  • added calculation of mode linewidths

  • 5 new examples

  • 3D confined samples and antiferromagnets (experimental)

  • other

New features#

  • TetraX now supports inhomogeneous material parameters, namely variations in exchange stiffess constant \(A_\mathrm{ex}\) and saturation magnetization \(M_\mathrm{s}\). Both attributes can now supplied to a sample as scalar arrays. For example, to set a linearly varying saturation magnetization, the following code snippet can be used.

    Mavrg = 800e6
dMdx = 10e6

sample.Msat = Mavrg + dMdx * sample.xyz.x

    The current average magnetization is now obtained with sample.Msat_avrg. For more details, see Examples Double layers of Py / CoFeB and Line scans and magnetization-graded waveguides.

  • The effective-field terms that correspond to the current magnetization state of a sample can now be accessed with

    • sample.Bexc (exchange field)

    • sample.Bdip (dipolar field)

    • sample.Buni (uniaxial-anistropy field)

    • sample.Bcub (cubic-anistropy field)

    • sample.Bdmi (bulk DMI field)

    • sample.Bidmi (interfacial-DMI field)

    All fields are return as MeshVector fields in units of Tesla.

  • One can now extract data along a curve of scalar or vector fields on a mesh. This can be done using sample.scan_along_curve() which accepts curves specified either by their start end and end points (will result in a straight line) or by supplying all interpolation points along the curve (enables arbitrary curves). This method calls the new helper function tx.helpers.math.interpolate_along_curve(). For a demonstration, see Example examples/linescans_waveguides.

  • The linewidths of spin-wave modes can now be calculated separately from the absorption() experiment. For this one can use the new linewidths() experiment or, alternatively, set linewidths=True when calculating the dispersion.

    exp.eigenmodes()
linewidths = exp.linewidths()

# Or shorter
linewidths = exp.eigenmodes(..., linewidths=True)

    Here the new linewidths data frame is the familiar dispersion table extended by the linedwidth columns (“Gamma0/2pi (GHz)” and so on). An application is found in the new example Linewidths of spin waves in magnetic film.

New Examples#

Minor Changes#

  • The visualization of waveguides and multilayers has been changed to include an additional mesh that hints at the full three-dimensional shape. For this, both sample.show() and ExperimentalSetup.show() now include the option show_extrusion which is True by default. Furthermore, the grid is now hidden by default which, in both, cases, can be adjusted with the show_grid option.

  • Apart from using tetrax.sample_average() one can also now use the more convenient sample.average() which only accepts the vector/scalar field as an argument and does not require to pass the sample object itself.

Other#

  • Updated User Guide with new features.

  • Updated Publications.

  • Internal restructuring of magnetic tensors to allow for more unified implementation with antiferromagnets.

  • Magnetic tensors are equipped with an update method that handles changes in material parameters but avoids unneccessary recalations.

  • We now support antiferromagnets as an experimental set of features including

    • all interactions except dipole-dipole

    • additionally, we support non-uniform DMI

    • visualiziation of AFM mode profiles

    Use on your own risk (and tell us your experiences).

  • 3D confined samples are now supported for FMs (without dipolar interaction) and for AFMs, both as an experimental feature.

Bug fixes#

  • Fixed a bug that gave an error when relaxation with least-square method failed.

  • Error related to numpy datatype and scipy sparse matrices fixed.

Version 1.2.0#

2022-07-15

New features#

  • TetraX now supports layer samples, which can be created with tetrax.create_sample(geometry="layer") and are represented by 1D line-trace mesh along the normal direction of the layer(s). For this, the plane-wave Fredkin-Koehler method has been expanded to infinitely-extended layers (preprint available at arXiv, submitted to AIP Advances). See Example: Thin film dispersion exact vs perturbation (Kalinikos & Slavin).

  • Templates for layer samples were added, in form of mono, bi and multilayers as possible 1D geometries in the tetrax.geometries submodule:

    • monolayer_line_trace()

    • bilayer_line_trace()

    • multilayer_line_trace()

  • Bilinear interlayer-exchange interaction is now available (only for layered systems), see Example Exchange-coupled bilayers (SAF). The interlayer-exchange constant sample.J1 (in J/m2) can also have different values between different layers in a multilayered sample, by supplying a list of values (see User Guide).

  • The eigenmode calculation ExperimentalSetup.eigenmodes(k=k_list,...) now accepts lists or 1D arrays as a parameter for k, e.g. to specify a non-equidistant wave-vector range.

  • Cubic anistropy (first order) is now properly implemented and can be used for both waveguides and layer samples. See Example: Fe film with cubic anisotropy, angular dependent FMR.

  • Rudimentary mode-profile visualization and animation has been added. If available, a mode profile can be visualized using ExperimentalSetup.show_mode(k=...,N=...). See User Guide for details and Example: Mode profiles and their animations (movies).

  • The numerical experiments implemented in TetraX are often based on seminal papers. In order to give credit to these works, when conducting a numerical experiment, TetraX now saves references important for this experiment to a bibtex file called references.bib, found in the sample directory. In this file, each entry contains a comment field describing how the reference was important for the computation. When publishing results calculated with TetraX in your research, please also give credit to the works which are important for the numerical experiments you conducted.

Minor changes#

  • When modes at a specific wave vector cannot be calculated, now, NaNs are inserted into the dispersion dataframe. Previously, this simply caused an error.

  • Warning message for magnetization pointing into the z direction removed.

  • Additional geometry added for waveguides, round_wire_cross_section_refined() which supports local mesh refinement (see documentation).

Bug fixes#

  • ExperimentalSetup.Bext is now initialized as MeshVector filled with zeros. Previously, an error occurred when not specifying any external field.

  • Automatic dispersion saving and perturbate-dispersion analysis have been reimplemented. Somehow they got lost in a previous merge. Saving of dispersions can be controlled with save_disp=True and ExperimentalSetup.eigenmodes(fname="dispersion.csv",...).

  • The director of uniaxial anisotropy e_u can now be specified as a triplet, e.g. [0, 0, 1], just like magnetization or external field. Previously, this caused complications with the possibility to set multiple uniaxial anistropies.

Other#

Version 1.1.0#

2022-03-31

New features#

  • Added the tetrax.sample_average() function available, which takes the average of a vector or scalar field in a given sample (can be volume, surface or line)

  • verbose={True, False} added to all numerical experiments, allows to silence all output (except warnings)

  • Saving vector/scalar fields to vtk files is now possible using tetrax.write_field_to_file() by

    tetrax.write_field_to_file(field, sample)

    or with the optional keywords

    tetrax.write_field_to_file(field, sample, fname, qname)

    As an alternative, the method AbstractSample.field_to_file() can be used, where the sample parameters is obviously omitted.

  • Added new equilibrium states bloch_wall and neel_wall to tetrax.vectorfields.

  • Added new geometry tube_segment_cross_section for waveguide samples to tetrax.geometries.

  • Plotting of scalar and vector fields on a sample is now possible using the plot() method of a sample object.

  • Pertubation analysis and reverse-engineering of general spin-wave dispersions according to Phys. Rev. B 104, 174414 (2021) is now possible within the eigenmodes() experiment, see User Guide Numerical Experiments.

  • Implemented cubic anistropy (linearized dynamic field not properly tested yet).

Minor changes#

  • relax() experiment now returns only a boolean denoting the relaxation success

  • magnetization is automatically saved into folder of experimental setup after running relax()

  • dispersion is automatically saved to into folder of experimental setup after running eigenmodes()

Other#

  • Populated User Guide and API reference.

  • Added more examples.

  • Indroduced MeshVector, MeshScalar and related data types.

Version 1.0.1#

2022-03-07

Initial release.