magnetography

Magnetography is the practice of producing spatially resolved maps of magnetic fields or magnetization in a material or region of space. It covers measurement, visualization, and interpretation of magnetic phenomena, including imaging of field distributions and mapping of magnetization patterns in samples or external sources. The term is used across physics, materials science, geophysics, and astronomy.

Methods used in magnetography include optical, scanning-probe, bulk, and spectropolarimetric approaches. Optical magnetography relies on magneto-optical effects such as Kerr or Faraday rotations to generate images of magnetic domains or field distributions, typically by imaging polarized light. Scanning-probe approaches place a nanoscale sensor near the surface or in contact with the sample to map field strength and direction with high spatial resolution; examples include magnetic force microscopy and nitrogen-vacancy center magnetometry in diamond. Bulk magnetometry measures average field or magnetization, and can be extended to spatial mapping with scanning or tomography. In solar physics, spectropolarimetric magnetography uses polarized light across spectral lines to infer magnetic fields on the solar surface.

Applications span materials science, geophysics, solar and space physics, and biology where magnetic labeling or external fields are used. It is applied to study magnetic domain dynamics in thin films, characterize superconductors and nanodevices, map crustal and planetary magnetization, and image solar magnetic structures.

Limitations include trade-offs between spatial resolution, sensitivity, and acquisition time, as well as issues of probe perturbation and calibration. Advances aim at higher resolution, faster imaging, and noninvasive techniques suitable for in vivo or industrial contexts.

See also: magnetometry, magneto-optical imaging, solar magnetography, magnetic domain imaging.